I've got two sets of 15s, Pro Comps with 3.75" BS that clear nicely, and Steelies with 4" BS that rub just a bit.

 

I have run 33x12.50-15 and 35x12.50-15 on a 15x10 wheel for many years and never had any problems at all. Keep in mind, this was mainly running in the sand dunes at 5-12 psi and never had a problem popping beads. It helps to give a nice wide footprint, which is what you want in sand and on the road. I would not recommend it for areas where you have rock as it will leave your sidewall more succeptible to puncture.

When I ran those set ups in the rock, I ran 15 psi and was always very careful but still never had any tire/wheel issues. I have seen others have the same luck as me but then on the other hand, I have seen where someone with a 35x12.50-15 on a 8" wheel had problems on one particular trail and I didn't. Pure luck sometimes.

I would say go for it. If you have the tires and rims, use em.