Suppose I have a matrix M, with rational entries. I need to go row by row and scale each individually by the smallest possible integer such that the entries in each row are integer-valued - anyone have an easy way to do this? It's a large matrix.

So, I have a list of vectors v1,...v8 - and I want to consider all {0,1}v1 + {0,1}v2+ ... + {0,1}v8 (I need a list of all 2^8 possible combinations). 

I can run 8 simple for loops and use the mod command, but that's inconvenient. Is there a nice way to do what I'm trying to get done?