Based on a recommendation I just got this http://www.3dmotive.com/product-modular-building-udk
Its a decent tutorial and at $15 I think it's worth it/priced right. Its short, and a lot of the ideas I already knew, so that made me bored. But there were a few key tricks and ideas in there that made it worth watching and buying.
I give it 3.25 stars out of 5. I like how quick it was but I think they could have pushed themselves to show more interesting and elaborate modular design.