Interesting ... I think you are referring to brokerages who give rebates? There are a couple of us out there:
Territoryre.com - flat fee, no matter what price range you buy in we get paid the same amount and we then rebate you the difference of our commission after closing. Our agents are salaried, no pushy sales tactics.
Zip Realty - they rebate buyers 20% of their commission back. unfortunately this means they still get paid more when you pay more for a home, not really incentivised to get you the lowest price. commissioned independent contractor agents (not salaried employees).
Redfin - they give 2/3rds of their commission back and charge per property tour after your first 2. They are also still getting paid more when you pay for a home. I believe redfins agents are salaried but they have changed their model a couple times so not sure as of late.

If you were offered that split from the listing agent on a particular property you were looking at i would be wary of those offers.

good luck!