if you are desperate to find a shopping cart system that allows you to authorize and capture an order from the back of your store for any reason, (i.e. comfort, etc..) then read this entire page and see if you feel the same way...

PCI Compliance Guide Frequently Asked Questions

In my opinion after reading this article, it just seems wise to either authorize or capture. and if you need to authorize first then capture the payment at the gateway terminal. yeah its an extra step but its probably a lot safer than you think...