Questions about the Triple Triad Roulette Rule.

I'm a bit confused about the Roulette Rule. I know what it does, but I'm having a bit of trouble finding an NPC that has it.

Is there always an NPC that has the rule, at any given time, or is there a chance that no NPCs have the rule?

Also, are the regional rules the same across the servers?

There are no NPCs that constantly have their personal rules set to Roulette. Sometimes, though, the "regional" rules will have Roulette on them, and an NPC can be used for Roulette wins then.

If you can't find an NPC that has the Roulette rule, you can always set it for use against other players.

EDIT: It seems that ffxivtriad.com added their regional rule tracker today, and it is separated by servers. So it would seem the servers don't share regional rules?

It depends on the data center, not the server itself.
http://arrtripletriad.com/regional-rules

You can update it yourself or let others update it.

Thanks for the info. I'll be sure to check it out when I get on the game.