I don't think that its a good idea to implement your own cron though it is tempting but i think you still can do the above with cron! you can have one cron common and copy this to other servers!
Mistake in crontab should not happen if you backup the cron before updating it! You can copy the cron to a file, update that file, then populate cron with the verified file!
cron daemon has problems! yes sometimes, but even with the script that you will make! it won't be much better than cron in hanging coz it would be simply a process after all!
Regards,
Khalid