It is an Akuyaku Tank (think Porco Rosso) in 1/72.

Marine is just for size comparison.

Add a few hull breaches and Orky "repairs", and it should be pretty good.

Agreed. By the tme you add a bunch of "Orky Goodness" to it, it should be unrecognizable!
Depending on the type of looted vehicle it is, you might want to clip off some of the other gun barrels, either that or hang stuff like enemy heads from them to represent them being just good old ork spikey bits.
It is a pretty cool looking model. Looks like it might be motorized, is it?

Nope, not motorised. It wasa fun kit to build, just got to wait for warmer weather to undercoat it.

Good thing you're not here. I probably won't be getting any warmer weather until March or April!

Not expecting it here for a while unless I get a lucky break.

You could always build a simple indoor spray booth like this one;
http://www.gamerabaenre.com/spraybooth.htm

That is horrendously complex for "simple" TW, I just scissored off the closing tabs at the top and 1 side of a firm cardboard box, cellotaped the seams/corner and placed it on its side (so its top and missing side are now facing me (the sprayer).
I can give a good full 90-110 degree arc spray, no mess. then either rotate the models, or rotate the box and replace the models.
When not in use, I put my spray cans in it so it takes up minus space.

I just yous a box and the kitchen Air extractor.

Well, it all depends on whether you want the fumes in the house or not.
Luckily, I have a heated garage so I just spray paint out there, leave the air filter on, close the door and wait for the fumes to dissipate.
If I had to spray paint inside the house, I would want some way to vent the fumes to the outside.

But I agree KMB, it is a rather large project.

I just prime by hand.