So you'd have to spline up to 720x540 before starting?

I'm just very intrigued by the potential of anamorphic 1080p to provide an alternative resolution that is Blu-Ray compliant and is able to squeeze higher quality into the same bitrates. I know a lot of projects use 720p as a way to incorporate lower quality footage in without standing out - I'm curious if 1440x1080p is capable of that as well, or if the seams show through. Considering the vast majority of fan projects are going to end up on SL 25gb BD-Rs, this resultion could be the sweet spot for providing quality. I'd imagine it might also reduce upscaling artifacts from projects attempting to scale to 1080p.