If you are looking for a higher end scanner than the ScanSnap, check out Fujitsu’s fi-6000 series. They are network scanners designed for a small office and look like they offer many of the ScanSnap-type features without being tied to a single PC.
Pieces of the productivity puzzle.
Do they work with Ubuntu Linux?
It looks like they will work with FTP so I think you can get them to work with Ubuntu.
Here is the “Fujitsu fi-6010N PA03544-B105 24 bit CCD 600 dpi Duplex Document Scanner” at newegg. Priced at $2,299 – not exactly a home-consumer price-tag, but if you need something like this for the office, it is much better than a cumbersome USB-SERVER.
http://www.newegg.com/Product/Product.aspx?Item=N82E16838115047