An HD Melty would rule, but I seriously doubt that French Bread is going to be doing that. I'm pretty sure by now they'd want to move on.
So, if anyone's going to do it, it's going to be the fanbase. And it will have to happen in one of two ways:
1) The game's engine is completely hacked apart. Every sprite, background, etc. is completely ripped, and using them as a base, fully new, HD art is put in by extremely talented artists.
- Pros: Actual Engine means that it can be "guaranteed" to be accurate. Wouldn't have to worry about timings or various mechanics stuff since all that would change would be the art. Ability to adjust things so that when characters speak, their lips sync properly (e.g; like Seifuku Akiha does) for all characters. Potential for even more animation on more animation-limited characters if things are figured out. Requiring the original game to work would be a good way to support French-Bread.
- Cons: LOTS of art needed. All illustrations, BGs, Char Sprites would need to be redone. Possible legal issues. The .p file format would have to be thoroughly figured out, and tools would need to be made to decompile/recompile things as necessary. Very costly in terms of time.
2) A Handbuilt engine and/or something like MUGEN is used as a base. From here, the game is recreated from the ground up.
- Pros: No need to figure out other file formats; depending on the solution used they would either be ones we invent or known ones. Freed from the limitations of the Melty engine. Ability to expand even further beyond the normal game's limits.
- Cons: Lots of art needed. Would have to be sure that everything is identical as possible or else the game will lose its "feel." Some graphical effects (Such as AACC's Heat effect) would be impossible or extremely difficult to implement in MUGEN and so would require a hardware-accelerated, hand-built engine. Some data might be impossible or nearly so to "exactly" figure out. Very obvious legality issues, since something like this would discourage people from purchasing the original game.
I'll admit, it'd be freakin' sweet though.