Hi,
If your thinking of DVI for improoved PQ, you may want to check out Immersive.com.
I use their HOLO3D computer pci card vid scaler which works with the Panasonic rp82 which they SDI modified.
If you decide to go the HOLO route there are several players that they will sdi mod for you. The concept behind the sdi mod is that the signal stays digital though the scaler and to the display device, there is no a/d d/a converson.
The HOLO will take any 480i signal you send it and scale it to any rez that your display can handel.
It has composite/svid/component and sdi inputs.
anyway you may want to check it out.
peter m.