Mmm.. apparently the original (non-HDMI) Sage Media Extender is actually a Hauppauge MediaMVP box ($150). Those now work as MythTV frontends (or, "extenders" if you prefer). Cool.

The video quality via component video-out is plenty good enough for 720p displays. For 1080p, though, a digital-out version would be preferable.

Within a year, I'd bet. But not there yet.