Not really TOS-centric, but one book I really liked as a kid was that Worlds of the Federation book. The drawings were obviously crude as hell, but I still loved the idea of it, and think a newer, updated version would be pretty cool.
With better drawings and graphics, of course (and not like those DW Encyclopedias which just slap in a bunch of photos from the show).
Wow, that's surprising. I thought I had every TOS book out there, but somehow that one completely slipped me by! D'oh.