Hmm. In theory, yes -- the N900, or really pretty much any computer with wi-fi, should be able to connect to a wi-fi aware device like the 6D / 70D. In practice, though, wi-fi interfaces are quite a bit more complex than Commercial IR remote interfaces; also, as far as I know right now, most manufacturers are keeping closer control over their wireless software, and aren't keen on seeing open-source versions of their tools...

Ultimately, it isn't likely that such controls will be making it into Pierogi any time soon, but a closed-source control app might be feasible. Anyway, I'll take a look at what folks have been doing with the Canons...

Edit: Well, maybe I'm wrong! Looks like the GPhoto guys are already supporting remote control for a number of different cameras. There's even been an attempt to get GPhoto running on the N900, specifically for remote control purposes (although via USB, not wi-fi). Might be more doable than I'd thought.

Edit 2: A very nice little video.