Hi Mr Kemper,
it's very cool that you discuss this in the community.
I still like your design proposal most, but i have a little suggestion.
A very important part is a good as possible readable display for dark clubs and also for daylight use like at a openair festival.
In the picture it looks like you want to use the same display like in the KPA(isn't it?). This seems to be the easiest and cheapest way, but due to good readable i think a lcd display is not the best option. First I was thinking about a vfd display, but they have an aging treatment and still aren't cheap. So i looked around how it seems about a monochrome oled display and i found one from Densitron Technologies. it's a 5.5" greenlight pmoled display with 256x64 pixels and the price for 100 of them is 'only' about 100 us-dollars (on the newark site). By ordering them directly by the manufacturer and with bigger quantity it might even be cheaper. maybe it isn't the cheapest option, but it could be a very good invest and an unique selling proposition!
Due to good readable in the daylight, it can be a good thing to mount the display lowered. and may a fixed or removeable glare shield. and an anti glare protection glass for sure.
hope i'm not to late for this suggestions...