I had this idea too, but the implementation is very hard. The lookup table you suggest is not very practical, becouse it would be huge and difficult to mantain (there are too many combinations). The alternative is using some occlusion detection algorithm, but they're complex on their own,time consuming and not 100% perfect.
I think the best solution to reduce vertex count is vertex merging (that is, removing one of two vertices if they're very close), that i do in BRIGL, and replacing/removing primitives. That is, you create a second set of primitive with much fewer vertices, or eventually leaving them out altogheter (for example removing stud completely). As Travis says, there's already a second set of primitives for studs.
I think the best solution to reduce vertex count is vertex merging (that is, removing one of two vertices if they're very close), that i do in BRIGL, and replacing/removing primitives. That is, you create a second set of primitive with much fewer vertices, or eventually leaving them out altogheter (for example removing stud completely). As Travis says, there's already a second set of primitives for studs.