Hi James,
This is very bright idea. this is one that I have thought of doing my self, if you can produce consistently and pre-screen these leads you will be love by agents once you hand them off to them, one because like you said, it is all about ROI (time + money) to obtain these leads, and for an agent time is so valuable, plus they only have to paid you once it is closed not up front. One way is that I was thinking on doing this is to contact for sale by owners, Expireds, Old expireds, Out of town owners and landlords. If you can stream line this, it of course can be done! Most of the work have to come in the forefront, of course you have to have quality leads and that means you have to be really good in pre screening them, these have to be Hot, or warm, not likely cold, but cold you can follow up on and then once they are warm, pass them on.
I know a poster have said that there are many companies already doing this, but they just use an algorithm and sale you leads that most of the time are no good, and it takes time to pre screen them. Why, I also thought of doing is, partner with real estate agents, say about 3 good ones, who won't drop the ball, remember, you have to have a good reputation and you are still tied to the deal, so make sure to pre-screen the agents your feeding the leads to, and I recommend 2 or 3, because ideally you will be sending loads of deals and sometime you can forget who you send them to etc...And also, I recommend you hit the agents that you are sending leads to and follow up to make sure they are doing what they are supposed to.
Hit me up, we can bounce ideas of each other.