I noted that we have no recourse through E-junkie if the merchant withholds payment. I've enjoyed promoting a couple products here but am extremely apprehensive about putting more advertising budget out there.
How about requiring affiliates to keep enough in their account (with auto-refill) to cover their current earnings? There are way too many small brands to give affiliates a great deal of confidence.
This would get you many more quality affiliates who are serious about their business.