I'm thinking of building a 12 x GPU rig, 8 of which will be running CryptoNight for Electroneum, 4 of which will be running Lyra2REv2 for Vertcoin.
All 12 of which could also be used for running Ethash to get Ethereum probably.
The equipments are on their way and I will be setting it all up in the next few weeks.
Would this work out alright?
It is possible, but the complexities listed by other users add additional (and mostly hidden) costs that you may want to avoid.