Filter to browse products by out of stock status in admin?

Hi everyone

I currently have a couple of extensions in the admin site of a 1.5.1.3 installation which add drop-downs to the product catalogue, so you can filter products by manufacturer or product category. I just wondered if anyone knows of an extension that lets you filter products by out of stock status? e.g. "Out of stock", "2-3 days" or "Pre-order". We take pre-orders on a lot of items, in which cases the out of stock status is set to "Pre-order". So it would be really useful if we could view all products set to "Pre-order" with such a filter in order to help keep track of pre-order products.

Thanks a lot

Adam