I just tried my origina galaxy tab dock on the 7 plus. It fits and the charging connector works. So you can probably use most of the old tab accessories with the new one
surprisingly the Belkin case from the first galaxy tab fits this new tablet almost perfectly. the only problem is its a little loose so i stuck some foam in with it and perfect till something better shows up.
Do you happen to know if the HDMI out on the old dock will function with the 7.0 Plus? I'd like to avoid Samsung's attempt to bamboozle me into spending $70 on the new dock and separate HDMI adapter if I can.