I haven't posted the most recent changes to the borders and rivers, but I'm pretty happy with what I have now. Region ownership will be sorted out later, but it looks like Poland will be in a similar position to the Eastern Roman Empire - fragmented, with either three or four of the five regions in 'rebel' hands.
I've found some maps on a Russian website, particular of Eastern Europe. The site is http://historyatlas.narod.ru/russia_eng/index.html. It seems to have quite a few maps that would be useful, *especially* where Eastern Europe is concerned. The maps all look very high quality.