All of the factors I'm familiar with are small, local operations; the larger operations tend to work up the food chain, financing less risky A/R. That said, they're all happy to offer me a commission every time I speak to them. So, I'm sure that the answer is, "yes, factors would pay you a commission on leads." If the leads are somehow pre-qualified you might even get 2%. I'd start by looking for factors in your area on Google, you'll find a bunch. Just call them, they're all born salesmen and will be happy to talk.
The problem is: how do you scale past one-on-one connections? Since we're talking about small, local operations, that's probably very difficult. Look for conferences, newsletters, and things like that, then advertise there. If you actually deliver useful leads, I'm confident you'll get a lot of referral business. But be prepared to deal with a lot of one-off relationships. Managing those may or may not be profitable.
(Now, if you built the software the factors used to manage their own business, then you could automatically suck in the data you need to manage your relationships...)