You could look into fitting the Vax components into a external box that could sit on your belt/guitar strap. I did something similar last year out of curiosity and got a set of 300 components to fit in a small tupperware box, then extended the wiring from the piezo's to suit.

My idea was to have one external Vax and then extend the piezo wires from the bridge of any guitar to a Neutrik RJ45 jack. Then I could use CAT 5/6 to connect the guitar to the external Vax. I finished the protoyype as a proof of concept but never went further into implementing this as I realised I would never used a large number of guitars unless I shot to rock superstardom (unlikely). I ended just transplanting 2 guitars and I've used them ever since.

There was talk on my threads around the time about what your would need to do to minimise RF interference etc and ensure that the right signal level from the bridge  reached the motherboard. If I remember rightly an idea discussed would be to change the impedance of the signal from the piezo bridge as it travels the extra distance needed to get to the electronics then to convert it back as it reached the Vax Mobo. This went a bit over my head and I never started working to understand it for the reason above. I tested the idea without any extra electronics to compensate for the extra distance with about 3 or 4 feet of CAT6 cable and short of a little extra background noise, it seemed to work. If you want to Vax enable your guitar at all costs, this might be a way forward for you?