The only center line tank is the Airworld that maybe a bit longer. I was quoted something like 450.00 for one. I have one off of a smaller hawk. I am going to see if looks too small.
As far as the elevator the bolt and mounts are fine. I have checked mine regularly and it has seen close to 7.5Gs and I don't see any issues.
The earlier versions used a long rod from the front. That would have failed long before the bolt. They did have to make sure the rod was bonded together properly.