I think it's going to have to be one of the Olympus dSLRs for a screen with live view which is fully articulated. The Sony a300 and a350 have a live view screen which does give some articulation but it certainly won't turn right around to face the sitter. The Nikons and Canons have a fixed screen and I'm not sure about Pentax and any others.

Perhaps if you asked in the Olympus Chat Room you may get some better help