I just checked this, took a look at the Nexus top 100 (both advlt and non-advlt so I don't think I can link it) and, of the top 10 most endorsed files, one is a body mod (number 4), another is a high res face retexture, I guess you might count that. The most downloaded mod is a high res landscape/architecture texture replacer. The most endorsed is a UI overhaul.
I lost an argument here about a year ago about the FCOM family vs body mods. IIRC, I came up with around 900k unique(-ish) downloads for FCOM and friends. The other guy came up with almost twice that for the most popular body mod. We used stats from the nexus, megaupload, mediafire, file planet, pes, etc. There was a fair amount of error potential, but I had to concede defeat. The interesting thing was that the numbers surpassed Todd Howard's stats for the total number of PC units sold, especially when you factor in that a large percent of people probably didn't use both mods. But most of us already knew his numbers were bogus (and no, there weren't that many pirated copies).

Anyway, it's just one of those things. We already know that six sells (look at commercials, games, book covers, etc.), and even if a million people want a more hardcoe, balanced game, there will be more that want T&A. What really blows me away is that something like the UOP wasn't number one. That's essentially a quantitative metric for irrationality.