The original XX A-8008 bodyshell I think is still avaliable through Horizon? Certainly a quick search on Google reveals a fair few places still listing it for sale
http://www.wheelspinmodels.co.uk/i/26496/
The 'Xcellerator' shell available as a repro from Team Blue Groove is what was standard on the run-out 'Kinwald' edition model - the rarest of the original Losi shells for the XX is the standard one that came with the 'CR' kit (A-8040) - this was quite boxy in appearance & most CR owners went for the more pleasing 'Kinwald' shell when it came to replace their original kit shells.
Anyway; good luck with your DoubleX Parrott - they really do go well, especially if you happen to race on a more traditional grass track where conditions can get dusty/slippery. I ran mine last year at a number of club& achieved some reasonable results against the more modern cars. If you ever come upon front arms or the fr bulkhead part, snap them as these seem to be most susceptable to breakage but are becoming hard to find
Adam - where did you finish last night in the end?