I would change your question to how can you find *great sales reps* who will work for commissions only. You don't want to waste your time with reps who can't sell but will take your full commission role - it is not true that reps on full commission are automatically more motivated to sell - there are many reasons why someone might accept a full commission role...so my advice is to recruit in sectors where paying reps full commission is common (ie office products, cell phones). Invite such reps to call on you, network with them to find out who are the best ones, and contact those ones directly. Avoid recruiting in sectors that typically pay a base salary in combination with commissions as these reps (the good ones at least) will want to have a base. Avoid any rep that is used to a base salary and will work for 100% commission as the chances are that they can't sell and need a place to hang out while they scout for a job that will pay them a base.

Good luck!