I require experts in Magento who are able to heavily modify the basic site to my requirements.

I require a Magento or existing .Net solution that has exactly the same functionality as Magento.

My solution needs to have custom features including

Front end ecommerce site using jquery, Ajax. For example gallery scripts and autocomplete search.
 
Admin Customer service area/returns 
Admin warehouse/stock control area – possibly to link into supplier data via xml or give suppler access to warehouse.
Admin accounts orders, invoices link into Sage accounting.

Separate script for email marketing like interspire if possible.
Recreation of site like this which is Magento.
http://www.matthewwilliamson.com/shop/

I am only interested in talking to people who have a good portfolio for ecommerce and code sites that pass w3c and are built using good CSS structures. No tables.

I do not require the standard Magento package to be reskined I am able to do this. It is people who know the structure of Magento and are able to customise it or have built a simular solution in .Net.