Beer style guidelines weren't invented by the BJCP. The DDR beat them by a couple of decades. With TGL 7764. Which pre-dates the BJCP by a couple of decades.
The big difference being, that breweries in the DDR had to stick to them. While breweries in the USA could do what the fuck they liked,
Why not honour these groundbreaking style definitions? What about having a festival of beers brewed according to the TGL 7764 definitions? There would be plenty of room for interpretation, as only OG, ABV, colour, rate of attenuation, etc. are fixed.
Here's a brief overview of the styles:
If anyone is interested, I can publish the full specs.