As has been mentioned before and I mentioned in here recently (but got ignored), just going to address level is insufficient.
Selecting the source for a txn should be to transaction level.
See the raw transaction API I've been working on, and please help try to break it-- it needs more testing.Selecting the source for a txn should be to transaction level.
The main motivation is to move forward with multisignature transactions, but it also lets you have complete control over the source(s) for a transaction.