There are quite a few mods that add extra belts, but Bob's is rather popular (and I've even played it!) so I'll see what I can do.
I'm seeing 20 for Turbo and 25 for Ultimate. Applying my normal numbers Turbo MR would be 40, LR would be 80, Ultimate would be 50/100.
Do you use the longer range pipes at all?
The main reason I would love to have the Ultimate extra long belts is that I can use the upgrade planner to upgrade all existing express/turbo belts I have to Ultimate without having manually re-do all the tunnels and to re-calculate tunnel length. So for me (but thats personal) the range doesn't have to be proportionally increased when going higher than Express, but that's up to you! I certainly wouldn't mind being able to build even longer tunnels!
And yes, I use the longer range pipes all the time. Works wonders, thanks for your work