Tom,
Outside of being an issuer (finding your own deals, managing them to disposition) which enables you a lot of exemptions from being licensed, the only two options left are starting your own Fund (Special Purpose Vehicle - SPV) or getting licensed and having your company affiliate with a licensed broker dealer. I have experienced all of these options.
If you are going to solely focus on a capital raising business, then I believe the broker dealer route allows you the most flexibility and aligns best with your investors. Your investors simply would be getting the same deal as the operator is showing. The issuer can pay the BD directly. The biggest con, you can only educate and market deals with operators that have been vetted and pre-approved to be on the BD platform. So if you go this route, you want to make sure the BD has a lot of quality deal flow in niches you have interest.
The downfalls w/SPVs are simply, you cannot receive compensation from the issuer for raising capital. You will have cost to launch your fund (legal, admin backoffice), you have to run or hire a backoffice for directly managing your investor base and all costs / fees must be between you and your investors. You, ultimately are adding cost to your investors on deals they could go direct to the operator and get better returns. So, the issuer wins, you can't collect anything in compensation from the issuer for bringing them your investors / capital. You probably need a min of $3M raise to make a SPV viable. The biggest pro is you have the most flexibility to do any deal you like.