Looks like we've got yet another A.C.E. game incoming, this time on the Playstation Portable, of all things. Ironically, it seems to have a far larger list of playable mecha and incorporated series' than the recently released PS3 game, Another Century's Episode R.
Given the relatively poor quality of ACE:R, I wouldn't hold my breath for this game being good for much outside of simple fanservice. If you can stomach the generally bad gameplay the series is known for, odds are the lengthy series' list will be more than enough to entice a purchase.
Overman King Gainer
Code Geass R2
Heavy Metal L-Gaim
Metal Armor Dragonar
Gundam Wing EW
Turn A Gundam
Personally, I'll be steering clear of this one. Honestly... I can't imagine FROM ever making a mecha game that plays well, particularly on a handheld.