Imageepoch have gone too, they probably bet the farm on Stella Glow, which was ridiculously high budget for a self-published handheld SRPG.
Press Play - shuttered alongside Lionhead.
Mitchell Corporation - Their website
stated that company activity has been suspended. I think they've become a licensing company as DotEmu obtained the PANG license and commissioned a new game to be developed by PastaGames.
Treasure - rumoured to be a licensing company, not developing any new games. But no one is quite sure yet.