UPS, Fedex, USPS bar code shipping labels

If KonaKart had bar code shipping label printing integrated within the shopping cart this would be a highly valued feature. I can imagine that this would be quite a task, but it could be an enterprise feature (unless you still wanted to make it a community level feature and capture even more market share). Even a smaller company like ourselves that has no need for the enterprise features would have to choose the enterprise extensions simply due to the time saving advantages of being able to click and ship orders directly from KonaKart (now shipping is done by re-entering copying/pasting the information from the KonaKart system into the shipping software).

1) Users would have there own UPS, Fedex, or USPS account numbers to use.
2) Intuit's Quickbooks accounting software does this for its users. Users can print a shipping label (UPS and Fedex) from the same screen that an invoice is created from.
3) An even cooler feature would be the ability to have multiple rates listed (ie UPS and Fedex rates) so that the order processor could print and ship using the least expensive route.

I have no idea how involved this would be, but I can see the value in it as a KonaKart user. It would be an awesome feature.