@Robert Larson May be tough. Agents make money when deals close. Since you aren't closing any yourself (you are doing a double close or assigning a contract) they really don't make money working with you. What is your pay structure? Are you going to pay them under the table? My guess is that this could be what is holding up finding someone willing to spend time on the search.
Wholesaling is also not really 100% legal. You are selling a property to someone else that you don't actually hold title to. You are selling something on speculation that you will be able to close the deal. Most broker/agents don't want to get tied up in something that may cause them to jeopardize their license. It isn't prosecuted against often so there is low risk as the wholesaler but if an issue arises, the listing agent could report what your agent was attempting to do and they could be in trouble with the state board.
This is why most wholesalers write their own contracts, do their own marketing, and work with off market leads.
WORD OF ADVICE: No many investors are going to buy a property from a wholesaler that is on the open market. If it is available to them, they will just make their own offers. If you have it tied up, they can just wait for your offer to fail to close and then make a similar offer to what you had. I am not saying this to be a jerk but to encourage you to think about new ways to find leads; bandit signs (almost always illegal but very effective), door hangers, knocking on doors, buying a direct mail list.
I hope that you are able to make this work. Good luck.
Some food for thought, most successful wholesalers find deals direct from sellers where agents are not involved, most of them do some type of consistent marketing, to find deal leads and most have buyers lists of approved all cash buyers to take them down. Not sure why you want to start a wholesaling business using an agent, you are actually defeating the purpose. Better to get your license yourself, stay on the legal side and then you can source all kinds of opportunities.