Miners already has those rigs
So nobody has to buy anything. Miners will make much more money for providing gpu power then when they are mining with the gpu's.
Don't forget that it will not only be GPU power, the mining rigs will look a bit different than some top ETH and BTC miner rigs.
I'm pretty sure that you will need a decent CPU and a lot of RAM also to get this working well.
They will probably need some adjustments to their machines but can be done
Sure it can be done.. I hope they will soon release a Whitepaper on how to build these machines
I'd like to be a part of this.