Race truck conversion - where

[Jez-i9scb]

Its seems pretty easy to buy a used 7.5T or 12T solid body truck, but I cant find anywhere on the net who offer conversions.

Plenty of places will sell a new £100k+VAT race truck motor home but I really don't need that.
Upgraded ramp/tail lift
some fixed lockers
belly lockers added
Compressor system
Onboard generator (maybe)

I've tried googling all sorts but no luck. There must be people out there doing this for a price somewhere between knackered old trucks people need rid of and £100k show homes on wheels

Any suggestions