Do they Have to be tubes though? Could you not use a modern flat screen TV?
Arcade collectors all know the day is coming when we have to make the move to LCDs. Either the tubes will all die or replacement electronics (like flybacks) will dry up. There's just something about that soft glow and the scan lines that adds to the nostalgia.
And believe it or not some people prefer tubes, especially in the fighting game genre
I do hope there's is forgotten worlds....best arcade shooter EVER