Could have used a bit more background research on if anyone else is doing this with the WR --> CB position group, given that there's no evidence of its success yet. As is we don't really know if it's an anecdote, a trend, or a strategy.
I do get the sense, very anecdotally, that recent college coaches are more apt to change the positions of their late draft picks and UFAs to ocassional success (e.g. Sweezy, Bruce Miller on the 9ers, Tukuafu if you wanna count him as a succesful transition). There's definitely been a very big move across the NFL to converting college OTs to Gs, and the FS/CB thing has always been pretty fluid.
Edit: Another thing (in addition to the recent college coaches thing) that someone actually could do and I'd like to see would be about late-round and UFA position switches. It's easy to say that late round/ufa picks don't usually pan out, but I'd be curious to see if the position switch late round/ufa guys pan out at a higher or lower rate than the non-position switch guys.