[Mas*Mind]

1. There is a slight problem of a cron job timing out (unlikely) or more possible someone closing their browser or whatever in the middle of the cron job. Some sort of backup mechanism if the cron job is set to busy all the time as if this happened it would never get out of the busy status.

Yes, that's a thing I though of also and still not figured out how to implement some sort of check so that this would be prevented.
maybe there should also be a busy_timestamp field to determine how long a semi-cron is in the busy state.

2. Possibility of having cron jobs only set off by a certain usergroup. It might be that we want to do quite a long cron job, for example the community bulletin. If this was the case, doing something like having a page come up

"Doing important server maintenace, please do not close this browser" sort of thing. So long you explained this to your moderators it would work. I know for certain that at least 1 of my moderators is going to visit the site every day.

good idea, I might consider that.