Only may 25 meters of runway is grass and the rest of the airfield is flat and paved. As for the B-17 Metal there's a silver p-47 and green P-47 so its gotta be possible to get the Silver. In FS2004 we had Repaints and that was fairly easy. I don't know how they do it in Arma2 though. The B-29s I believe were the Pacific theater so I'm not sure I44 is the place but you may see one in the "Hell in the Pacific mod" coming out soon. The Lancaster ah what a great plane...If you get the Lancaster then you have to build a dam and a think you know where I'm going with that one hehe.
I thought I might make mention after looking at THIS IS IT page you sent that this may make good reading for you as well http://www.homeofheroes.com/wings/part2/09_ploesti.html Its a page dedicated to Operation Tidal Wave ,The Ploesti Raid. I read it years ago because of my love for the B-24D but if you like vintage and read the Stories you'll love it as well ,not quite as long as "This is it" though. You know Im surprised Ive never heard of "This is It".
Also YouRek it would be great to see the Horsa Gliders considering they were a huge part of the UK Involvement in D-DAY right along side the C-130sI believe they took off from Lincolnshire Airfield. Bunches of them crash landed though and alot struck power poles.