the way plesk allows to create reseller is the same as creating client account. just simply we need to increase the domains and other resource limits. the only issue in plesk reseller is that when reseller adds domain name, it won't send email to that domain email account. if it could, then reseller could customize the email with their own company and other details etc.

however we have sold some reseller plans with plesk and our resellers are still happy thou :-)

Ali