Why Are There No Comprehensive Online Variety Guides?

While recently going through a hoard of Ikes, I have again encountered a familiar challenge to variety coin collecting. Namely, there do not seem to be search-oriented variety resources. Most variety sites are organized around error types, which are then broken down by year, mint mark, and so forth. For popular categories like doubled dies and repunched mint marks, the biggest catalogs often overlap, but not completely.

The catalog approach does not lend itself to the basic coin hunter question: what am I looking for on this coin? For example, when you sit down with 143 Eisenhower 1972 (P) $1 coins, what you really want is a list of all the interesting things to find. I end up constructing the search list myself by scribbling down a few notes, and opening multiple catalogs and articles on my iPad. Then I comb through all the resources, jotting down notes and little diagrams, and tossing any items that might be impossible to see. I also note the sites where the varieties can be found. Finally, I might sketch all the places on obverse and reverse to examine closely, so I can search for all potential finds in a single pass.

Every time I go through that compilation process, I think to myself that surely many other enthusiasts have done exactly the same thing over the years. The CPG and Strike It Rich are organized by denomination, year, and mint mark. Do books exist that provide more thorough search lists of minor varieties? Are there web sites that I just haven't figured out yet?