[UPDATE] - Sony Japan has officially confirmed production has ended for the PSPGo, a plucky little innovator - it will be remembered fondly.
A report over on Andriasang suggests that Sony has ceased production of the PSPGo, presumably to make way for production of the NGP. The poorly-selling device never really caught on and without the mega-selling Monster Hunter Portable games appearing on the PSN store, it was never likely too.
I'd love to pick one up once prices have bottomed out, regardless of its perception as a failure, it does look fantastic and I have enough PSN games to make it a worthwhile backup device. Hopefully a price cut will see the last of them fly off the shelves into good homes.