Dollar cost averaging approach to Bitcoin investing?
This can be done today.

Dwolla lets you send money to Mt. Gox on a schedule:
 - http://help.dwolla.com/customer/portal/articles/164379-multi-payments-schedule

You then can leave an open market order to buy bitcoins, e.g., a bid for 10,000 BTC.

The moment new funds arrive from Dwolla, Mt. Gox will attempt to execute the remaining part of the order using all USD funds available in the account and those bitcoins will be purchased at the market price at the time.

Of course, this assumed the account is not used for any other trading, as that open bid order would be triggered from any BTC sales that occur.