Thread: modular modular case
KAHNCO: dead. As far as I know, it was vaporware. Geeklapeeno, which is similar, was also much talk, no walk.
As for the SP-1, it's conceptually interesting. I do have some concerns about a portable case made up of plastic segments being durable in the long-term, though. It would probably be fine as a studio enclosure, though.
Another idea might be Elby Designs' Construct-a-rack Series cases: http://www.elby-designs.com/contents/en-us/d39.html These come in 42 hp and 20 hp segments, with various options for depth, side panels, mountings, and covers. With these, you do have the ability to build cases with strap-on covers for portability, and the metal construction should prove quite durable over time/use.