I vote for rebuild. I am currently restoring a Tiger 1 myselfe and it is real nice. Can't wait until it is running strong again
It sure sounds like you have to spent alot on spare parts and dedicate some time, but when you are done and manovering the tank again you will feel it is worth it. I guess you will like it more than ever and maybe you will not drive it so hard anymore hehe

Building a stürmtiger also sounds nice, but I still say rebuild. Anyhow, I wish you good luck!