It still feels disingenuous the way they talk about these announcements as "partnerships". All they've really done is talk some people into letting them host preexisting Android apps in their store. It's a zero risk venture for all the developers involved, but using the word "partnership" creates the impression of a greater interest on the developer's part than actually exists.
Not really, just "hosting" a preexisting app won't work, as I understand it all apps need to be at least recompiled with calls to the Ouya SDK (especially anything using in-app purchases, which is every app that isn't 100% free). Plus, many apps would need extra work to support 1080p, most current apps aren't designed for 100% controller use with no touchscreen, and of course not all existing apps have the free demos that Ouya requires. And if you read the statement by the XBMC guys there's definitely more going on, as they talk about getting access to early prototype hardware. And in the case of XBMC, it would make sense for them to match the rest of OUYA's interface with their own (not saying they are doing so necessarily, but it would be lazy for a media player to have a different interface than the rest of the console).
Oh, and I just read more about XBMC for Android, and they are very specifically targeting "set top boxes" like this, not normal Android phones and whatnot (and full 1080p for videos is an important part of it). And of course it's not really a "preexisting Android app", as XBMC isn't on any store yet, best you can do is compile an early version yourself. And they already talk about how one company "sponsoring" the Android XBMC allowed them to write a hardware accelerated version for that device, so I could see an Ouya partnership allowing the same thing.
The system looks like it's really shaping up. Now I just wonder if it's capable of running hd 2D titles. If it could be my source for games like Bastion, Rayman Origins, Guardian Hero type games, I'd be in heaven. 
