If you are doing well and looking for a complete web based multi-channel ecommerce suite as oppose to point solutions, you can checkout GoECart 360[GoECart.com ]. It's not inexpensive but it is totally integrated. You can also check out NetSuite along the same lines.
GoECart 360 is an All-in-One SaaS Ecommerce Suite that contains:
1.Advanced Ecommerce Platform
2.Multi-Channel Order Management System (WebStore, Call Center, Marketplaces like Amazon.com, eBay etc.)
3.Inventory and Warehouse Management