TYPO3 Core

I would love to be able to redirect the standard 503 error page with the up-side down TYPO3 logo to some other server where we host a simple static emergency page with some basic content of our own.

I have 404 handling working nicely and our loadbalancer handles many scenarios when webservers are completely down, but not the in-between scenarios where TYPO3 is in a sort of half-up state like when there are no pages or no TS template record. Since those situations also essentially mean "site down", I would like to treat them the same as the others and show the visitor something useful instead of a TYPO3 exception which is only interesting to the admin.