Is there a way...

To have some products be able to be purchased and placed on back order, while other products are one time purchase only?

Example:
One item I sell, the customer should be able to purchase as many as they want, I only have a set amount in stock but they can be placed on back order and shipped when ready. They should be able to enter X amount in the qty box, and if they order more than I have in stock it should be placed on backorder.

The second item I sell are more of "one of a kind". When they sell there are no more. One time purchase, no back order.

I can't quite figure out how to do this. It seems like I can only set up all products to be as many purchased as the customer likes with backorder OR set the number allowed then they are out of stock.

I hope I am making sense! It's very hard for me to explain.

(If this thread is in the wrong place feel free to move it - I wasn't quite sure where it should go!)

This is a reasonable request, but it will definitely require some custom coding.
If made convenient to use, it would not only need discrimination code in product listing and info pages (or shopping cart page), but an admin switch and a database field added for the product input. Not a trivial job.

You could approximate the function by setting (in Catalog > Categories/Products > product editing page)
Product Qty Maximum: to 1.
This would keep a customer from buying more than one, and you would have to turn off the product as soon as it was purchased so nobody else tried to backorder it.

Thx gjh42 - That's what I was afraid of. I don't really want to be messing with the code, I was hoping for something simple. :) I will keep your work around in mind... not really sure if I want to 'risk' doing it that way or not.

If the one-of-a-kind items are clearly identified as such in the description (worth doing anyway as it adds "uniqueness" value), a "sold out" type of flag which will show after purchase should notify any but the most obtuse or impatient customers that there is no point in trying to buy the item.