Not feasible with TITAN at the moment because every transaction has to be scanned with every account key and so many account would make scanning too slow.

Currently bter.com implements BTSX deposits by asking all clients to send funds to one account btercom, and to put a custom memo message. This approach leads to errors and forgotten/mistaken memo messages. A better approach could possibly be for exchange to register unique Bitshares X account name for each user in the format <customerid>.btercom
This approach would let each customer have a personal deposit address and eliminate need for memos and would reduce errors. However this approach introduces need for exchange to manage hundreds or thousands of accounts and I am not sure Bitshares X client is ready for this. Also, funds deposited to customerid.btercom would likely need to be auto forwarded to a collection address like btercom.
Would like to hear your thoughts on this.