Attached (I hope) is a database I put together a few years ago. We went to each state online and found the document signing requirements. Let me say, ahead of time, that:
1. Rely on this database at your own risk.
2. This was specifically for structural documents, although I would suspect the requirements are similar for other disciplines.
3. Images of the stamps are only included for those states in which *we* did business at the time.
4. Although the state may say one thing about what their signing requirements are, the local jurisdiction may or may not follow.
I hope this is of some use to my fellow CADDers.