Breakthrough!! I was worried that I wouldn't be able to give this model justice in the render stage, but I just spent 5 hours learning about render layers and compositing, and have finally managed to render without crashing. This was rendered in 4 pieces. I haven't messed with the compositing yet, so the masks are maybe a little too obvious, but at least now I know with a little work I can get the high quality render I'm looking for. It only took 38 minutes to render all 4 layers too.

Now to finish up the modeling and start texturing. The engine is all but complete apart from the exhausts, so the hard part is done. :attn: