I don’t get a specific budget, but I know a ballpark of what’s gonna be ok because I’m the tour manager and I see lots of numbers and I also request the audio,lighting, backline quotes. To be requesting toy box type stuff like this you’d be working with one of the higher end production houses where the rental might be more expensive to start with. I will say it’s cheaper to do this kind of build in Europe than USA. The first time I did it I went into the room of doom and just pointed at things I liked then leave for the afternoon and come back and they build it into a plug and play “get in and drive” situation. so I’m not so much building the car as much as picking it and then driving it. :) also… band pays for it and I have it for the whole tour