Id be surprised if we would let Vieira go to another club outside the CFG, Given all the roles he's had since being with us I'd say we (as a group) would want to keep him to ourselves.
There maybe the situation where Paddy wants to try someone else, in which case fair enough, but I actually think he comes across as a very loyal person & if he ever did leave we we would be first in the queue to get him back if that situation occurred.
He will obviously have a big affinity with Arsenal for ever, but I reckon how we've treated him since retiring give us at least an equal standing in terms of his affection now.