Due to lack of space in our 8 gallon conical FV, we augmented the brewery with a 4 gallon stainless steel pot. There is a nice Amber Czech Lager fermenting right now, about 2.5 gallons.
A good quality 304 Stainless pot will work just fine. Easy to clean. And, just keep the lid on it during the ferment. No need for an air lock, or blow off tube.
A 4 gallon fermenter was ordered from Blichmann Engineering to augment our brewing capacity, but it will not ship until next week.