no, but i'll never forget what one print designer once said when someone asked him about tablet computers with screens that you can draw on.  he said that being hunched over tables had caused generations of illustrators and designers to have serious back and neck problems, and that it was much better to have a situation where one could have the arm in a comfortable position while sitting up and looking at a screen.

that said, i know there Cintiq displays made to be upright (have been for years).  those seem like they could work like easels.