I think it will make you more attractive to some webmasters but i would question which type. It seems to me that there are webmasters who make sales and those which dont. I would guess that those who make sales would want their own hosting so they have more freedom on what they promote.

It wouldnt appeal to me for that reason, but then it really depends on your rules. Are you willing to allow them to promote other paysites aswell as yours? Also you need to be aware that they can put anything up without you knowing about it, unless your going to reguarly monitor each account, which has an extra cost impact.

Personally i think you should pilot it first. Theres no point in spending the extra money if your not going to get and retain the sale type webmasters. Why not pilot it among your trusted webmasters then go "live" for everyone else if you think its viable?

Then again i now nothing so just my thoughts.