Ordering items not in database

I have a client that has alot, I mean alot, of items and is switching from a static site to ZC. He has most of his items moved over but does not like linking customers back and forth between sites.

On the old site customers simply browse a page, see what they want and click a link to a secure order form and manually enter the item number, name and price.

We all know how it works in ZC. But the question is using ZC's shipping cart and checkout function for manually ordering the items not in the database yet. Almost like a special order form.

For example, the sell hamradio equipment. They also offer everything from MFJ. MFJ has thousands of items. So it's almost impossible to list them all. So they list what they usually have on hand. But the old static site with the manual order form would allow a customer to shop the MFJ catalog and manualy enter the item number in the order form for purchase.

Is there anything out there to allow this feature with ZC? I've used Miva in the past and there was a module for this feature. So I figured there might be one for ZC.

Thanks everyone
Dave