I have a 2 yr old 10D lying idle since getting a 5D.
Whilst I have to agree that the lens becomes a major issue at airshows, the leap in resolution/file size is incredible once you step up. I can easily tell which body was used when I have used both the 5D and the 10D on the same day at the same airfield.
Try Park on Google and check.....although I do not buy in the UK.