Given their unique design, springboards are one of the greatest assets AND liabilities of the
Handspring Visor. I believe that the specification is an open one, and if some other design (
Apple!) also used it, it would help adoption / development.
It boils down to a chicken and egg problem...When there were major problems getting the Visors made and sent out the door, there was really no market for the springboards: development plans may have slipped at that time. Now there are no problems shipping Visors, but a real dearth of springboards is making the choice of an esoteric standard (vs, say, compact flash like the TRGpro) seem foolish.
I wish they would jumpstart the open-source / hacking community with software examples and a CHEAP (cost +$5) "expansion" board that could be used to easily interface with the Visor. I'd use the latter for prototyping instruments, interactive displays, programming chips in the field, accessing the microphone, and a ton of other uses.
It will never happen.