There is only one right now. I've been looking extensively for a solution and waiting for Elgato but apparntly this is the only one out right now.
Hauppauge HD PVR USB
Has component and composite input as well as optical. Everything besides the compsite input is passthrough I believe.
Confirmed wayyy too much lag for gaming.
Uses elgato's eyetv for mac. Doesn't come with an IR blaster that is compatible for mac.