So, I think I invented a thing. Here's the explaination I came up with last night:

The instrument I am developing will be a combination Bass, Guitar and Mandolin.
It will have 5 strings, four of which will be paired in two octaved coarses, similar to the bottom four courses on a 12 string guitar, but in fifths like a mandolin. The scale length will also be the same as a 34" scale bass as it is being built upon a Cort Action Bass V. The final string is a bass "Eb" mirroring the pitch of the lowest course but an octave lower.
The string gauges will be .50 and .28 for the lower Eb tuned course and .40 and .18 for the higher Bb tuned course.
The Bandotass will also have a guitar humbucker in the neck position to better suit the higher tuning which will be controlled with a single toggle switch and the master tone.

I had the bass laying around and decided to make something a bit different with it :P
I'll post loads of pics as I'm making it.