As far as I know Audi is the only place to get anything prop shaft related and I am pretty sure they only do it as a complete prop so if yours is ******** you can look on ebay etc to fine a second hand one...
TT's are shorter (as Welly found out) so you 'can' use the front half of it IIRC but I am sure he will be about later to confirm... Golf R32 would also be a suitable donor as would an A3 quattro
Righty... after having a quick look on VAGCAT (VagCat boards) it seems the doughnuts are listed separately but how accurate that info is I don't know... front doughnut is 1J0521127A, rear doughnut is 1J0521307C
Not sure if that will help but may be a start... tbh the dealers aren't too bad at finding parts once you give the reg number
I check the engine mounts mate... there should be no reason why the prop will come anywhere near the rack or PS pipes unless its moving too much on the mounts...
£82 plus vat I was looking at the fitting instructions for the lower engine mount bush and there appears to be a bracket the goes between the engine and the mount. mine doesn't have this for some reason , should I be putting one on there?