One forum users seems to have an idea on how to test the possibility of a RAW mode in the Samsung WB550/WB500 models. See in the dpreview Samsung forum. No answers yet by people who have tried the test.
RAWsumer reviews at the Compact Reviews Organizer
CANON: G11 S95 G10 G9 S90 SX1is
PANASONIC: LX5 LX3 LX2 FZ50 FZ100 FZ40/FZ45 FZ38/FZ35 FZ28
RICOH: GRD III GRD II GX200
SIGMA: DP2 DP1
NIKON: P7000 P6000
CAMERA DIARIES: Panasonic LX3 Canon G10