And,...the reason I'm looking for a service on the web instead of rolling my own is simple, I live in the land of flakey power and don't want to take on the expense of trying to keep something online 24x7 out in the country.
If you have your own domain, and your own web-hosting company hosting that domain (you do not have to do it yourself), they are responsible for keeping it online.
Of course, in the event of a power loss at your location, I'm not sure how you expect to access any web server.
So, back to the OP's question. What are the alternatives to Cosm? If there are any.
Do you mean services that someone else pays for?