Yes and no. Or sort of. There is support for generic PVR front-endedness -- a different add-on than the preceding MythBox add-on, which only browsed Recorded Programs. Though like I mentioned, it's a couple of releases behind MythTV (and since Myth changes its db format regularly, that's a serious incompatibility (though ultimately that's MythTV's fault, since the way it is designed requires all front-ends to open a live MySQL connection to the back-end database....)).
Anyway, the thing about the new XBMC PVR functionality is that it is front-end stuff only. It does have an EPG and a UI for scheduling and managing record rules, but it requires a separate back end, and on Linux that means, yep, MythTV. Ans as you're no doubt aware, MythTV is so screwy to configure that any change to ditch part of it is a welcome opportunity, but the back-end config is probably more convoluted than the front end, so this is just a partial fix.