I found this game, too and had the same thought. They use extra lorom to combine these games. Technically the same thought as I had already a long time ago, too.
The problem is that the exlorom is limited to 8 MB. Means we cannot combine the 4 AST roms at the current state (4x4MB=16MB).
What could be possible is to combine the roms without the intro/end (slideshow) patch so you have 4x2MB=8MB. But many other patches might be incompatible which use space in the region between 2-4MB (like the msu patch). Their code needs to be shifted to a space between 1-2MB.
Then, and this is horrible: you must re-direct every bank pointer to the new one.
I will not go for it, too much trouble for too little outcome. It is convenient, sure, to have it all in one candy rom, but the effort and restrictions to renounce on the slideshows makes me rejecting this. I got used to having 4 roms and with this trick:
you also don't need to rename anything anymore (only at the setup).