Subsequent thoughts from me. If I can find one for cheap enough when the time comes, I'll definitely just pick up a used 8x10 enlarger. It just makes more sense. This just assumes that, when the time arrives that I build a new darkroom and want to enlarge 8x10 stuff, I'm not going to have too much cash to throw around, which isn't too far fetched. Just sort of a contingency plan of sorts. I've thought about making an enlarging back, as it were, for my Deardorff, but I have to wonder - would it really be rigid enough? If I wanted to go that route I could probably also pick up some beater 8x10 somewhere for pretty cheap and permanently convert it to an enlarger.
As for cropping, while I suppose i would want to do it once in a long while, I think the likelihood of me needing to crop much is pretty greatly reduced in 8x10. I'm more likely, I think, to be cropping 35mm negs shot in a less contemplative manner.