Just a thought. What about running a very short string of those tiny Christmas, er, holiday lights, clear or frosted, and attaching them behind the base of the vu meters . You could run them so there is a socket behind each vu, and put bulbs in as the original ones blow.
The backlit ones may look a little funky next to the meters that still have bulbs burning inside the vu box brightness-wise, but would make the previously dark ones easier to read. Just attach the leads to the power supply in some way, right?
Or it's just a firehazard. Nevermind..