Aside from the possible account sales moving to external sites or platforms, is there any other reason behind ruling this out? The main issue is the account sales in the first place, it would be best to allow a single account for each person only (I know it will be hard with the use of similar VPN's and etc... but there are other forums that actually identify each users regardless of them using similar VPN's and etc...). Not sure how hard that is to get implemented, but I think it will be worth the hassle. Also certain users can have their accounts reviewed (by mods) and if their behavior fits within the forum rules, they could create other accounts (for the right reason and not for joining in other signature campaigns), something like only a single account (per person) is allowed to have a paid signature.