Does anyone know of a reliable hosting company, that allows own nameservers, ensim pro, miva or oscommerce, linux, mysql, squirrel mail, etc and dedicated servers with high spec, and good tech support for resellers?
Your recommendations valued

All Ensim hosts will have the options you have mentioned but you also need to remember that in order to activate Miva you need to purchase a license which is fairly expensive when you take into fact that there are several very good free options available out there which are as good if not better than Miva.

Also look for a host which has Ensim Pro Powertools installed which has some very nice one-click install shopping carts built into the control panel via Powertools.

Thanks for your mail, I am in such a situation currently hosting at rackshack where they claimed MIVA was included, however when we came to activate we found that no licence was included.
As of today we have not found a open source shopping cart which is effective, if you know one please inform me
regards
PhoenixEagle

The one which I can highly recommend and has a very big following would be osCommerce which is included in the Powertools setup.

You can find more information here http://www.oscommerce.org/