You didn't mention gluten, but when we were free of ds's sensitivities (gluten/dairy/corn/soy/eggs/avoiding nuts in general) and vegetarian I found this yahoo group vegan and gluten free
really helpful. There are TONS of recipes in the files, many of which are free of nuts and soy as well. I'd think doing lots of (tolerated) legumes would be the place to get protein from as well, although I might rotate to prevent any future sensitivity issues. It's really tough!
We were in this position at one point of time (soy/nut free vegans--I was vegetarian for 12 years b/4 dropping ds's allergens, and ds was veg from birth). Just want to share that I ended up adding in meat after a few months on our elimination diet, as I felt terrible on the restrictive diet being vegan (I had highly relied on soy and dairy prior to cutting them out). The health benefits we've had since adding in meat (and some really WAPFy, TF foods/food prep methods) have been _amazing_. I just think its something really worth looking into, esp. when you are dealing w/ gut issues, as Californiajenn mentioned. For me personally, I believe it was the best health decision I've ever made for both my son and I. Of course, we each need to figure out what works best for our own bodies! I just really wanted to share that though!
A great resource for adding in TF types of foods (if that's something you're interested in) that is also vegan is http://www.greensmoothiegirl.com/