At a Toy show in Japan, the TakaraTomy display revealed Encore #17 - Cassette Big Missions Vol 2, containing Steeljaw, Ramhorn, Ratbat and Slugfest, to be released in June. (happy to see ratbat, so I can finally get a legit one with ears)

http://blog.hobbystock.jp/report/2009/01/tp0094.html

The display also shows:
Encore #15 - Cassette Big Missions Vol 1 (Ravage, *BUZZSAW*, Eject, Rewind).
Encore #16 - Combaticons.
Masterpiece Grimlock.
Chrono Label (has a big screen, so maybe has other electronic/digital features).
Mickey Prime, both colour and grey versions.
Henkei Ratchet
Henkei Inferno
Henkei Dinbot
Henkei Hotshot with Jolt
Henkei (Red) Alert
Henkei Smokescreen
Minivehicles Brawn, Beachcomber, Cliffjumper, Wheelie, Cosmos, Warpath.

This year is gonna be expensive...