I think it would be best to partner with a local operator of local currency exchange booths. They already have all the necessary licences and infrastructure.
What would the motivation be for the local operators to participate? They have a flow of customers because of the agreements they have with Western Union, etc. Not just any person on the street can do transfers for WU and other networks. I doubt these operators want to create competition that will cannibalize their business.
Additionally, generally where remittance transfers are high (India, Philippines, Mexico, Bangladesh), the restrictions on the networks allowed perform exchange services are high as well.
Now for bitcoin, there's no technical restrictions stopping anyone from performing exchange services. A person with a smartphone, a few dozens of bitcoins and a wad of local cash has the tools to become a solo operator providing exchange. Because most (nearly all) of the transactions will be cashing out bitcoins (e.g., from remittance payments or maybe income from microtasks or oDesk type of work) so this individual will end up needing to sell bitcoins to restock the wad of cash. This will create a distribution system where bitcoins flow up the distribution chain to larger exchangers who trade internationally. In this distribution chain then cash flows down to the local exchangers.
If this network were to be built in this manner then it isn't a singe operator that can be forced to use official exchange rates and since a single party didn't have control throughout the distribution chain, a single party doesn't have the info for reporting the details on all transactions. The ability to know how much bitcoin-related activity is actually occurring would be difficult even.
Bitcoin's nearly-free transactions make it so that there is no exchanger too small. Instead of there being formal currency exchange booths, there is an exchanger that your coworker is related to, for instance. So you trade with the coworker (for a small fee) and the coworker does the trade with the relative that does perform exchange.
It probably needs to be these personal type of pre-existing trusted relationships otherwise the alternative, the craigslist model (directory of anonymous individuals pitching their offerings) simply provides criminals intending to steal a steady stream of unsuspecting marks.
I don't know how you get from here (no awareness of bitcoin, no exchangers) to there (ability to ask around and end up where someone you know will trade with you, because they know someone who will trade with them).
It probably won't occur quickly if left to happen organically yet at the same time that approach might take no longer than trying to get bitcoin exchange approved formally.
There's one other angle though. The reason remittance payments are sent in relatively larger amounts (e.g., $250 at a time) is because the transaction also includes a fixed per-transaction fee, so sending a larger amount helps to make the overall fee on a percent basis lower. Since bitcoins can be sent in small transaction amounts the sender can help encourage bitcoin adoption by augmenting the traditional remittance payment by sending a small amount of bitcoins as well. If Western Union ends up costing 15% or more then it is in both the sender's and recipient's best interest to try to help bitcoin become a worthy competitor to the traditional money transfer services. Now with a Bitcoin SMS Wallet provider ( https://coinapult.com/sms-wallet
), there's an easy way to drive the adoption of bitcoin simply by sending a little over and seeing what the recipient can do with it. [Update: Coinapult is U.S. and Canada numbers only, but they are figuring out how to go to more countries.]