I serioulsy doubt there will be any Final Fantasy for the DS, if so it would be along the lines of FF:CC (not a part of the original series)
Sony owns part of square... they will probably make PSP-titles.
There are chip for the PS2 that allows booting appliactions from the memory card, I am sure such a chip could be created for the PSP.
But chipping a handheld would probably be hard.
Do you deny the existance of the DMS3?
Oh, and to whoever said it... making mod-chips illegal is stupid, there...
If you are looking for non-rechargeable ones I must recomment IKEA, at least if you live in sweden they have cheap as batteries that have stood up quite well to the competition in a few reviews.
A 10-pack is 20SEK which is about $2 (when the dollar was strong... about $3 now)