Although a couple of these scans are from other sources (the Falcom desk calendar, Falcom World Guide books, etc.), most of these come from the Sora no Kiseki FC & SC Special Collection Book, a monster of an artbook that I highly recommend.
Incidentally, it was also the first product I ordered directly from Falcom.
Anyhow, product info, as usual!
Eiyuu Densetsu: Sora no Kiseki FC&SC Special Collection Book Item No. B36 ISBN: 4-7753-0487-9 Price: 2,300 yen
As I scan more, I'll update the albums. Additionally, if you have a particular character you want me to scan, post your pleas in here and I'll get to it.