I am running the PWJDM/Odyssey set up and have no complaints about it. To do a proper above tranny relocation I would suggest a smaller gel type battery. You can see the fun I had installing my rbc in the thread posted on the engine section.
For what the PWJDM bracket is, you can make your own with access to some welding and preferably a bending brake/laithe (depending on where you are). You can make it so the battery sits long ways against the frame rail as opposed to along the drive line.
If I were to do an in cabin relocation it would involve eliminating the rear seat and the battery mounted on the passenger side inside the suspension square. Probably the floor board using a nice heavy Optima red top.