ROMs for a 128K Mac can be replaced with 27C256 EPROMs with pin 1 lifted out of the socket and jumpered to pin 28. (Programming pin needs to be tied to +5V for Read Only useage.) If you can get the part number (there were at least 3 different "64K" ROM versions), I may have an original chip to replace your bad one. Worst case, I can fire up the Apple II EPROM burner and burn a pair of 27C256es. This is the first case of a bad ROM chip I've heard of, but considering the age of those chips, I can't say I'm terribly surprised.

Vertical stripes with no "BONG" or error code usually means the CPU isn't running, and that usually is some sort of ROM problem, usually from an upgrade come loose, as has been mentioned. Kudos for excellent trouble shooting!