I know someone who has a collection of around 16 of the ‘small’ UJ crosses - 44x20 mm as fitted to T3s and similar older twins. These are relatively simple to replace (even I managed it without total disaster).
He also has around 16 of the larger 50.2x22 mm crosses. As I understand it these fit some of the twins post T3s, and with some work moving the position of the clips can fit others as well.
He used to rebuild UJs for people (many moons ago) but has long ago moved and not been in touch with the Guzzi Club.
He’d like to know if anyone, or even the club itself, is interested in taking these on as a batch. If so, please contact me and I’ll put you in touch with him.