Having 3 custom fields in the "Product", "Listing" and "Order" pages for internal use.

It would be extremely handy to have 3 custom fields in the "Product", "Listing" and "Order" pages for internal use. Example: We use Sage accounts and I would like put the sales code against the "Product" and or "Listing" and or "Order" (Order page will only show whats in the field at listing stage) for reporting purposes, so in your backend database it would show customfield1 but on the frontend for us the title would be editable. So because these are not linked directly to any sales channel it would be quite easy to implement. It's just like the "PickBin" field, not on any sales channel, purely for internal use. Thanks Jason