I didn't think this would happen! Konamistyle will release a combination soundtrack for the WiiWare Contra and Castlevania games. Contra Rebirth contains rocking retro-style arrangements from the history of the series, and Castlevania seems to be the same. It's coming out on the same day as the huge Castlevania collection box, March 24.
Konamistyle page: http://www.konamistyle.jp/ecitem/item62572.html