| I've got the same problem on my Leroy Geiger bass. My guy in NY wouldn't do this repair unless he could take off the top. His approach is to plane wood away from the inside of the top at an angle, so he could glue in new sections of wood with good overlap (if I describe it successfully). Here in Germany, I have had repair people tell me that they could do it without top removal, and would meticulously carve and fit new wood into each and every little crevasse, leaving as much original wood as is practical, if only they had the time and space, which none of them do! (Advice to young aspiring luthiers: Come here! You need to train or at least apprentice here to work, but once you do you will always be busy, and the customers don't fuss about price!) Anyway, your bass sounds like it's valuable enough that you should do what you can to keep it from degrading further, which will happen if you let this problem go. In your favour is the fact that it is not a 30k+ bass, and you don't need to limit your options to the top bass dogs. This job is more fine woodworking/restoration than fine luthiery. No knowledge of tone/violin mechanics is required. I would first go to your local string instrument maker/repair shops (including acoustic guitars) and get an opinion. Check out their work. If you get a good feeling and the price is right, then go for it. If not, how about an antique furniture restorer or other high end woodworker? You take a risk since they probably haven't worked on basses before, but if they know their craft, are reputable, and agree to take a try, I bet the results will be good!
Robobass
Disclaimer: Not responsible for f&%$ed up instruments resulting from my f&%$ed up advice! | 
