so I decided to bite the bullet and I ordered 2 x 32GB SDHC cards (legit hardware, no bootlegs) and a photofast CR-3100 to try to get a total of 64GB on my PSP. (I used SDHC since no 32GB microSDHC's are on the market as of 12/1/09)
The PSP seems to recognize the raid'd memory cards as 49GB (about a 24% capacity loss, compared to the usualy 5% capacity loss due to overhead) but once you connect the PSP to a computer (winXP system), it only recognizes 31.9GB.
I created a 33GB testfile to copy to the PSP CR-3100 with 2x32GB sticks and it did not work, so it appears there is a current 32GB hardware limit to the various photofast adapters on the market.
Any feedback is welcome, I hope I am wrong.