We have a heavily moded X-cart, it's beatifully tailored to the needs of a direct market ecommerce business that sells direct to customers, dealers and distributors foreign and domestic and has every custom feature we could imagine....
(We had planned to connect it with Intellisoft's ManageMore. Unfortunately the closer we got to implementing MM the more we realized how horrid, buggy and difficult to use MM was. )
During the comprehensive search of ERP solustions that followed we stumbled upon insterprise suite.
It looks brilliant, exactly what we need. The one catch is that we need a nice plugin that will allow us to
tightly integrate our customized x-cart with interprise suite. This would be a full two way x-cart integration plus the addition of some extra custom features (like net 30 payments, rule based discounts, etc.)