1. More often than not, the best deals never make it to the MLS. You should be highly engaged in finding deals on your own and utilize a realtor to help get it to closing.
2. A realtors stock in trade is knowledge and time. None that I know will work for free. Either you pay them a fee to put in offers or close on a few a year with the same agent. The second option is best because it builds loyalty and trust.
3. No one I know successful in buy, hold or flip makes "offers every week for properties in every state, and see who bites." No realtor sees that as a serious investor and would be violating his/her fiduciary responsibility by making offers and managing sales in a state they are not licensed or knowledgeable. If you have agents working on your behalf in states/areas you do not live at least within a 2-3 hours is problematic at best and at worse financially dangerous. A smart agent will cater to his local pool of investors and "outsiders" are not a priority because when word gets out that the great deals you are getting are being done by an agent for someone not local, the agent will want for work and income in a short period of time.
4. Investors that I know with your type of goals, either gets a license and support their own team to build a portfolio or brings enough business and income to one or maybe two agents IN THEIR AREA that bonds them to the investor.