One pose I like to do, especially for church directories is to have the parents sit on the stools *its a pain when the parents are the same height, so it would be nice to be able to stagger them* and then if the kids are around 10 or so, have them stand beside each parent, but sometimes they are to short for this, which is why the blocks are nice to have.
In the studio I use to work for, they had foam blocks in a few different sizes that the kids couid stand on, it was pretty sturdy, must have been dense foam or something.
Phone books would work, why didnt I think of that? I wonder where I can get some that are a couple inches wide. My local book is only a cm wide. Perhaps I should just stop by verizon and ask, gotta find them first. 
cinder blocks are an idea, where do you find them? lowes/home depot?
Thanks for the link sevilla, its loading now. 