Hey Sean!
I love the idea of playing Titanfall on a stair machine! I don't own one (and I don't think they'd appreciate taking an xbox to the gym) but if there's a 3DS or PSP mech game, I'd totally give it a shot!
I didn't put it in the email (would have made it way too long and gushy) but I've played I think all of the Telltale games since Back to the Future as "one episiode start-to-finish" treadmill sessions, and really appreciate all the effort someone there put into the UI / gamepad controls (its much more comfortable than trying to use mouse+keyboard).
I've never tried Dota2 because of how much Awesomenauts stressed me out, but if you're interested, I'll give it a try over the weekend and report back.