Hi,
I dont know of any such device off hand that can work that high (30 amps), but you can make your own i guess if you get some copper buss bar (rectangular cross section) and drill and tap several holes in it for say 6-32 screws or something like that.
The problem i find with screw terminals however is that they are a pain to work with. You have to keep unscrewing and screwing to change components, and you also have to get the lead of the component under the screw just right or else it pushes out or squashes the lead. If you go to put two components under one screw that's really a problem because one lead pushes out usually.
See i've built several power supplies with rather heavy duty screw terminals (look for 'terminal blocks') and i can tell you they are best when you dont have to keep changing wires or components to the screw terminals, like for more permanent installations. For experimenting they do work but they are a little bit of a pain.
If you use copper buss bar, you probably want something at least one-eighth inch thick or better, and say one-half inch wide.
If you are still interested you can look for some heavy duty terminal blocks as they might help if you dont want to roll your own.