maybe yes... dunno. Never searched for it. Maybe radio Shack up there ? ( we don't have radio Shack down here... used to be here but not anymore )

Maybe in fact some car parts shop like Advance, Kragen...

But honestly I don't think necesary a buss bar. Engine bay devices only requires ground for ECU and Regulator and both can it be tighten up with same ground strap. Lights have the ground on radiator core support. Parking lights by chassis itself same as wiper motor. Horn is body ground too, and no one of them are critical like regulator and ECU.

but you have the option to make it as your wish