Thanks to everyone who has responded, it's given me a few new ideas. I'm intrigued by the solution of editing a local database and using a web service to sync back to the geodatabase. Melinda, I realize that you all have created a customized service, but could you go into just a little more detail about how that works?
Just before I revisited this thread, I had the idea of editing an Excel file on whatever device and then manually loading that into the geodatabase, but I think I'm looking for a solution that's just a little more elegant.
Pursuing the track of editing a local database with SQL Server Express or similar, I don't think SQL Server Management Studio is the right tool for field workers. What interface would users have to edit this local database?
Also, does anyone think ArcPad would be a viable solution to this problem?