is there a way zeroshell can be used as a transparant proxy for example but it not be a single point of failure? IE lets say the box crashes or gets powered down. is there a way I can configure things to proxy thru the box when it’s available but bypass it if is not?
It depends on what is your budget. Unfortunately in most cases you have a single point of failure, unless you have everything dual.
You could get a router that will divert the traffic depending on a health check of the box. If it is up it will send the traffic through ZS, otherwise it will send the traffic directly to the gateway.