Guessing it was part of the gaming compact update that passed recently but while rooms can offer spread limit if they chose the option for true No Limit Holdem now exists in AZ and the biggest card room in AZ Talking Stick Resort already offers it.

The following are the guidelines and stakes
Stakes 2/3 Buy In: $100-$300
Stakes 3/5 Buyin: $300-$1200
Stakes 5/10 Buyin: $500-$2500
Stakes 10/20 Buyin: $1000-$5000
Stakes 25/50 Buyin: $2500-NO CAP
Stakes 50/100 Buyin: $5K-No Cap

Of Note also 5/10 and above is timed rake not per pot.