Note that there are also six button fighting pads that should be compatible with the Steam Machines too. The one in particular that I find most interesting is

Note that there are also six button fighting pads that should be compatible with the Steam Machines too. The one in particular that I find most interesting is the one for the upcoming Hyperkin RetroN5 -- it's a six button bluetooth controller with a microswitch based thumbpad (much like the ones that came with Neo Geo home units from the 90s). http://hyperkin.com/blog/2013/03/retron-5-details-revealed-from-the-midwest-gaming-classic/ http://hyperkin.com/blog/2013/03/retron-5-details-revealed-f...