[davidjgraph]

> Reliability is key, your service needs to never ever fail.

Then that sounds like it need a serious full time commitment. The OP seems to be looking for a specific category of ideas that require minimal maintenance, rather than any ideas.

[rmc]

100% uptime is impossible. Remember you can get 99% uptime (2 nines) if you're down for 4 days in a year.

[martinkallstrom]

"Never ever" is at least two nines.. perhaps three. 4 days of consecutive downtime would probably hurt a Cron as a service-service a lot in terms of user happiness.