Today I was trying to relist one of my sites for selling superfitblog.com. But I was not allowed because another user sold the site having same domain name around 4 years back. So, I think its a bug over here. Admin please allow sites to be relisted if its done by different user and also remove permanent limitation of relisting site. Thanks
It's been on the to-do list for a long time already. It's very far down the priority list of things to do though.