(NB the following is just what I've gleaned from people I know, and not necessarily 100% correct or the official views of Sustrans - just my understanding of the situation)
I'm not sure if this has been covered in the thread or not, but I believe the view of sustrans towards it is that there's a resignation that something will happen, and that BRT represents the best of a bad bunch. If the money isn't spent, the money will be lost (not saying this is a good or bd thing). Sustrans don't 'support' it as such, but are involved to make sure that cyclists/walkers interests are best represented in whatever happens - the BRT route disrupts a lot of work which sustrans has put in place already.
(please remember, this is re-hashed, and not neccessarily correct - don't want anyone to get into hot water - so do not quote me!)
The new bit of path currently being built from the girder bridge to the self-store warehouse is nothing to do with BRT (as someone not on this thread suggested) but part of the Connect2 scheme - improving access to the network for all.
There were 2 guys from Sustrans canvassing support on the North side of the river yesterday lunchtime
a little bird tells me they'll be there today too, freezing their tits off!