May be a little late to help you John but I had a scanner at work that I couldn't find the correct drivers for and found VueScan from http://www.hamrick.com/ It's a little pricey for a scanner interface but solved my problem when I had to use that particular scanner. There's a demo version that adds a watermark to the scan but the full version doesn't.

List of supported scanners:
http://www.hamrick.com/vuescan/vuescan.htm#supported