That is why your model of "leads for business" is so attractive
I think there is a lot of merit in generating leads for business. Just recently I was approached by a company who did not have the ability to generate leads as well as what our network did in their industry. They offered me half of their company with me still retaining my IP. (A little bit more complex but just illustrating if a business doesn't have leads to sell to, it's very difficult for them. Leads are King!)
It also allows you to develop your websites, get them ranking, set up automated emails to your purchaser of the leads and it's a set and forget, move on to the next one.
A lot of companies will try and push to pay you on a successful sale. I will NEVER take this option unless it is the absolute last resort. There is always a happy medium when it comes to a lead price. I work out what it would normally cost them to generate a lead and then add "Choice 4U" tax on top as we believe we are a premium supplier.
I define a lead as a Contact Name, Phone and Email. If the company wants more info than that they have to pay even more because of the drop off rate.
"He who owns the lead, owns the wealth".