If you are just building one of something, and particularly if it's going
to be a lab queen, then look at the evaluation boards from the FPGA
vendors. Documentation will be complete, but basic -- you'll get a
schematic and an example application, and the rest will be up to you.
Beyond that -- I'd be surprised if there's not more out there. Some sort
of a general-purpose data acquisition card with an FPGA in it seems an
obvious sort of thing to sell to people just like you.
--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com