Yes, I would suspect it's generally possible with most games. Razoola already did it with Crossed Swords II and Ironclad and Zintrick have been converted. Probably more I'm not aware of. The NeoSD is basically doing this conversion on the fly btw.
CD games and cart games both contain essentially the same data. For example PRG files on CD games are equivalent to P-ROMs in carts. Both hold the 68k code. They hold it in slightly different formats but converting from one to the other is pretty straightforward. Similarly CHR files on CDs are equivalent to C-ROMs in carts, holding the sprite data.
Music is very different between the two systems and would be the most challenging part to address. Large games that load a lot would have challenges as whenever the program makes calls to the cd drive, there's obviously no equivalent to that on cart systems. Small games that load into memory once and never again would be easier.
I've never converted a game like this, just going off what I know from programming the Neo and reading the dev wiki.
Your making it sound easy here. Which mind you, I wouldn’t know myself as I don’t know how to do it, but if it is this simple & easy to do, then I find it odd that it took so many years for it to be done? Surely your minimizing the hard work of the pioneers who did these conversions (Jeff Kurtz, HP Man, and Razoola) by saying so?
Just get a NeoSD Pro. It already supports Neo Turfmasters CD and 50 other CD games, eventually all of them.
And this is news to me. The first time I’ve ever heard of it.
Other then Metal Slug (combat school mode), Neo Turf Masters (extra course), and Stakes Winner GI (?), I’m not aware of any other significant bonuses or extras implemented into the CD versions of neogeo cart games.
And regarding the 8 cd exclusive titles, the ones that are the most relevant to this type of a discussion, here is the way it stands as of today:
Ironclad - done & perfectly so, as it was the original cart rom code given by SNK through the Nintendo Wii release.
Crossed Swords 2 - done & excellently so, as Razoola went all out with his time & effort.
Zintrick - unfinished but fully playable, yet could be as good as CS2 if work was to be continued & completed.
Final Romance 2 - unfinished but fully playable, same as Zintrick.
Samurai RPG - technically possible but involves too much work, for now at least.
Kof ‘96 Collection - irrelevant & of no interest as it is kind of pointless.
Neo Geo Special - same as above.
ADK Special - sane as above.