I was impressed: thought we'd be there for a couple of hours and ended up having the gates locked behind us after about 6 hours! Their aircraft collection is excellent - 43 airframes in total (including replicas), but there's loads more to see in the various preserved buildings around the site, many of which have been restored to wartime tableaus. There are 2 nose cockpit sections you can sit in: a Jet Provost and a Canberra. They also have 1 of only 2 WE177's on display in the UK with an interesting selection of other bombs, plus a superb turret collection.
As for taxiing airframes, I'm only certain that their Victor and Camo Bucc taxi. Most of the aircraft have had their engines removed. They are restoring the following to taxi status over a few years: Mosquito, Dak, Anson and possibly their Argus. According to the 2007 blurb, their Gannet is one of only 2 airworthy examples, but having seen it I'm not sure that this is still the case! The Auster may also be a flier!
Their Halifax is the only complete one, but as you say, it was reconstructed from numerous airframes. Here's the origin of the bits:

The 609 Sqn room is very nicely presented, as is the station chapel (much of the insides of which came from Scampton). They also have a corporate suite: the Elvington Room. One of the highlights for me was the WW2 control tower, complete with meteorological equipment, charts, diversion information etc. It was great to have access to the base archive rooms (loads of photos!) and the bomber command tribute hall with small cinema was really well done.
The history of Elvington as an operational RAF (and prospective USAF) base is fascinating: I never knew 2 French squadrons operated from there! Apparently, it's still the longest runway in the North (10,000+ft) and the large concrete apron can be clearly seen from space!
Definitely worth a visit!
Gully
PS. Bum!!
