Yep, fair to let the community decide.
Defo. no performance benefit in supporting Suprim, as most 30XX cards end up at around the same point for the model once tinkered with. My opinion was based on feeling it was easier ‘packaging‘ the product (metaphorically) for sale and have a bit of a unique selling point, no checking of compatibility lists for potential buyers - i.e. it just works with every GPU from 30XX generation.
You are right though, another future product could end up being incompatible.
Whilst I doubt we will get many bigger product variants being released this generation, aside from perhaps ’halo’ products. Hopefully the next generation of cards (esp. Nvidia) are not so power hungry, so the trend for bigger and bigger GPUs doesn’t continue.
I wasn’t sure if staying below 10L was a principle of the project, if so, I totally respect that. Saying small as possible would be beneficial for transportation/shipping and for those looking to carry to different locations regularly. I don’t think anybody would notice the 10.5L under normal usage though.
My Sapphire 6900XT will fit either way. 
