Guys,
SanDisk's 16GB microSDHC card slips into retail, T-Mobile's G1 - Engadget
Ah, it seems that the 16GB Micro SDs are out already in the wild. So at most, just wait till December, and you'd be able to get them at reasonable prices of like 35 ~ 40 USD per piece (Or even better, wait for the class 4/5/6 versions to come). Plug them into the Photofast 5400, and voila, 32 Gigs on your PSP without a single physical mod.
Cheers.