Can Finder and the "open" command treat files with .sh or other typical extensions just like .command files? I am looking for a way to inject some more extensions into the OS X launch services database systematically so that when clicked, they execute in the terminal app just like .command files do by default.

Things like .ksh, .sh, and .csh would be nice to start, but I assume once I figure out how to add one, it's easy to do the rest.

An answer specific to Lion or Snow Leopard is fine, so a general-case answer for all OS versions is not necessary. It would be great if this were scriptable and wrote directly to the Launch Services database so I could automate this rather than going to finder on each mac and doing a lot of clicking.
If a file is opened with Terminal, and has the execute bit set, then Terminal will execute it.

Get Info on a .sh file and set it to be opened with Terminal, and click the Change All button.