ON CURRENT LIST
1 Multimelta on a fragile vehicle (pretty much dies if sneezed at relies on rest of the army distracting your opponent.. or on the implied threat of his purpose making other things get to do more by drawing fire), 1 relic blade (relies on close combat, relies on your opponent tank not having moved more than 6"s (needing 6s to hit) and would struggle against a dreadnought (6s to glance)..I wouldn't classify that in my "I have anti tank" bucket

The conversion beamer is fluffy and nice (and shiny new GWness).. it relies on your opponent always being as far away from you as possible..remember its optimal anti tank range is basically the board width away. (although it can do some damage at anything from 18-42)
The sternguard point- is basically what Tim said.. sometimes there is a points saving, sometimes there isn't, Here you have the choice of in 1 3rd of your games being able to skew the odds in your favour by having them as one solid block (-1kp)(whilst in other games using them as you have written them). I'm a big sternguard fan..and your load out is interesting..it covers there one weakness, that time in game when they want to charge. I haven't read much elsewhere on it..and I haven't played that config.. but its 20 points extra on each squad to make them jack of all trades.. the question is are they master of none..
I would hypothesise,and thats all, that spending 40 points and guaranteeing 4 EXTRA kills on a charge..might stop you being able to charge..and if it didn't you might be charging a unit that is too good for your sternguard to be used (e.g you don't want to throw them away trying to kill 6 terminators ) Whereas those points (the flamer and the pistol) nearly give you another multimelta speeder

(or special weapons for the scouts squads) That removes the plas pistol requirements and takes the pressure off you feeling you have to try to use them as assualt troops in game. (silly 3rd option.. you know the plas pistol costs the same as the lascannon yeah?

)
Apology- I'm sorry my game has been a tad off in this thread and possibly my advice too drip drip to be of much use.
I know your busy at the moment.. but when will you get a chance to playtest your builds and evaluate your lists for yourself? (self appraisal is a great learning curve and helps you to laugh at advice given by people ,like me, on ta intervebz, and to be more confident in your playing style (mine is described by others as rather blunt but very heavy) I'd always strongly suggest playtesting with bits of fluff, chesspieces and existing models with a friend to see how stuff works before running out and buying 5 thunderfires etc

(a good measure of a friend is if they'll let you use a wolverine toy as a dreadnought

)
Future
I've stared at your lists (really I have I've spent a good 2 hours in this thread) I think its better if we take a slight backwards step and go back to page 3 (post32 to be exact) and see if we can come up with something from that list that works for you (gamewise, modelwise and fluffwise)
Here is a quick merging between your p32 list and the tips that followed it to use as a an alternate base if you wish..I've tried to keep the fluff over gamey prime in my mind.
YOUR OLD LIST MIXED WITH NEWER BITS
HQ=330
Kantor 175 (with his orbital pie plate and super bolter and slow fist- which at least has a synergy with the sternguard)
Master Of the forge with conversion beamer & Bike 155pts stays far back and takes maximum shots.Try to hide him from the bulk of forces snipeing off one thing at a time.( That termie squad or that AV14..and only that one thing till it is dead)
Troops 400
10 Scouts with camo cloaks and sniper rifles 1 missile launcher=180 (ok so thats a lot, but in most objective games thats 2 squads who distract your opponent, can claim objectives..more just to annoy than actually hold them.. he needs to send a close assault squad in there to get them...don't try to get all the objectives TRY to get 1 and annoy your opponent enough into him not having one whilst the others are contested..the missile *might* be able to get a side shot at a weak tank)
10Man
SM lascannon razorback flamer= 220, (5 man las is the cheapest possible las, the flamer half goes off in shooty tank to contest objectives and bring the close assault pain (maybe reinforcing a scout squad that looks strong)
Elites=555
10 sternguard Drop pod 285 (they can choose how to arrange themselves each battle, you could have an empty pod land and contest and objective just to annoy and distract whilst the others set up conventionally, you could split the groups to hold objectives thanks to kantor, or you could stick them in the pod and have them up close and shooty with +1 attack if kantor joins them to rapid fire and then get squashed on a weak flank of your opponents..(although so many things false flank or are fast enough to avoid this watch out for any talk of flanks

)
Ironclad Dread, 135 (in this set up your going to be using them to draw fire and to support faster troops as they go for objectives.. they are an area denial wall..(like you don't go near the deciever)If they get shot to death..good thats a few turns that everyone else is fine..if they don't get shot your slowly pushing that area denial radius closer to him (at 6+d6 a turn) like a net(anything (but fast) will get caught up in it and forced to consider them the worst thing in the world), they won't be all that much use in dawn of war because of the extra 12"s they have to make up.
Ironclad Dread, 135
Fast Attack= 100
Attack Bike(2), 2x Multi meltas=100
Heavy 100
Thunderfire=100pts (Sits in good cover (praying no one can be bothered to shoot it..mostly going against eldar and other fast targets that might threaten your base)
1485-5 Long ranged antitank,34 minis +5 vehicles, 6 scoring units 10 killpoints.
Questions outstanding would giving the pod to a dread(bring back the flamer) be more or less versatile (would getting a first turn bishop sacrifice of either be acceptable,which is more likely to get his points back or cause most disruption etc)..You could use the 15 to give 1 of the sternguard a lascannon depending on your local game and how you approach the pod problem..although I believe you would like to use the points giving the 5man flamer
SM squad a power weapon

.
Hope something there helps
KMB