The only problem I see with a PC (with say nvidia 7800 series component dongle) at 1080i is syncing the interlaced video to the passes of the interlaced signal, which can be tough but not impossible. With a high end CPU you could simply bob-deinterlace it on the fly in a program like VLC at 60hz and you might not even see the difference at the HDTV end unless you have almost no motion in your videos in which case you should just make sure it only runs at 30fps so both fields draw the same frame of motion = no deinterlacing or syncing issues!
Another choice would be to get a HDV camera (make sure it has 1080i and not just 720p - a little expensive for now), export the videos in its MPEG2 format and then upload them onto the DV tape via firewire or stream them directly through the camera into the HDTV so the camera syncs the interlacing correctly. Futile use of a 5000+ dollar camera maybe.
