MapInstall cannot be scripted to create a gmapsupp.img (plus setting it up on linux is a pain). I'm pretty sure the <4GB gmapsupp part files - shouldn't be too difficult if mkgmap can associate the address index for the choses tiles only.
Right now for scripting I can only see how to create gmapsupp part files without address search.
Cutting Europe into smaller parts using osmcut or similar takes quite a lot of time, plus if you compile a full map of Europe anyhow already - would kinda double the work. And you would need to adapt the area rather often as osm data increases...
Having mkgmap split the map into parts would be great therefore (and also put out some sort of parts.list similar to the areas.list from splitter would be even better).