This is the second thread you open regarding Shotacon anime. For the lack of response, I think it's safe to assume that most of us aren't interested in it. I started watching the third OVA of Boku no Pico (I really thought the new character was a girl) and that was not a pleasant surprise. Regardless of that, I have found some straight Shotacon in the AniDB and in other H OVA that I've watched.
The most commonly known is Kodomo no Jikan, the OVA from 2000. I have watched it and it's not bad, but it's not my style.
There is also some action in Chikan Monogatari. However, that's only available in the Japanese version of volume 1. Those 8 minutes aren't available in the R1 release.
The other one that I know of is Soukan Yuugi.
There is a very small segment in Bishoujo Comic Lolikon Angel: Mitsu no Aji, but it's irrelevant since that's a loli anime.
That's all the ones that I know regarding shotacon. Oh! And Enzai appears in AniDB as Shotacon-Yaoi. No idea about that one, though.