Hi Jim,
Don't worry - I won't get tired! Never with such supportive readers as you!
Black Cross/Red Star Vol. 4 is more or less completed, and Eagle Editions has promised to publish that one already by the end of this year. Let's hold our thumbs that the printer will succeed the first time...
Then I have a similar series for which I hae received contracts from Ian Allan in the UK: "Eastern Front Air War". Four volumes will be published:
"Barbarossa: The Air War": Due mid 2007
"Stalingrad: The Air War": Due late 2007
"Kursk: The Air War": Due mid 2008
"Eastern Front 1944-45: The Final Air Battles": Due late 2008
Those books have more of a "strategic" angle, while the Black Cross/Red Star series are more operationally focused.