Brake Fluid that doesn't affect paint?
Not that it addresses the underlying problem (leaking brake / clutch lines) - however, I just read, with great interest, about a new brake fluid offered by CA. It's called BR092 SILICONE BRAKE FLUID.
CA's description states:
"Developed for the US Military, silicone brake fluid (DOT 5) is the most advanced brake and clutch fluid ever devised. Never needs replacing, non hygroscopic, doesn't damage paintwork and boiling point of 260 degrees C (500 deg F). Compatible with the seals and hoses used by all manufacturers. Because it absorbs virtually no moisture it retains the high boiling point for life and can be left in a braking system indefinitely. Non-toxic with no known harmful effects too."
It's ridiculously expensive - but, maybe...