Thanks for all the great advise. It looks like both Toddmanqa and I have similar projects going. I am definitely getting a lot out of the replies to this thread.
I just have a few more questions:
1) The 2x2 & 2x3 idea that Nealtw had for the forms... is that to provide some interlocking of the slab sections to keep them even in case of settling or just a convenient way to create a partial form when mesh extends past the section being placed at the time?
2) It looks like the majority say that rebar/mesh is overkill. However, wouldn't reinforcement give the slab some crack resistance if there is some settling?
3) Is 3.5" good for a basement slab? Is it a bad idea to go thinner?
4) If placing the slab in sections as we discussed (i.e. sections in direct contact) do I need expansion joints around the perimeter with the slab meets the foundation?
Thanks again for the great advise!