The best results I've seen for upscaling involve Avisynth's nnedi2_rpow2 and ResampleHQ (a gamma-aware downscaler). I'd certainly say it's "detail preserving".
Assuming a PAR of 72:79 (since we're using 711 rather than NTSC's 710.85), the GOUT has a DAR of ~64:27 (2.37:1) since 711*72/79=648 and GOUT has 274 visible scanlines, so 648/274=2.364963503649635...
The idea is to use nnedi2_rpow2's field interpolation to get from 720x480 to 1440x960. (This'll take care of many of the aliasing problems as well!)
Next, you use ResampleHQ to downsize to 1280x540 (or what-have-you) by using the extended parameters to take care of the cropping. It's better to pass the crop values to ResampleHQ rather than crop manually since ResampleHQ can make use of the pixels-that-will-be-cropped in its downscaling algorithm, thereby reducing the likelihood of screw-ups at the borders.
(Note: You'll have to double any crop values that you computed since you'll be running ResampleHQ on the double-size output from nnedi2_rpow2.)
If someone posts a frame (preferably a PNG) from GOUT here, I can hack the code up rather quickly.