You can get a standard regulator for the same price,or cheaper,than one for a paintball bottle. The only difference is how fast you will go through the CO2. If you are using this on a 72 gallon tank,you will be going through bottles every few days if you go with a paintball regulator. I used a paintball set up on a 10 gallon,and a 24oz bottle would last for 3 weeks.
I now have a 10lb bottle,that I paid $25 dollars for on craigslist,and it cost me $25 to fill up. I expect it to last for 9 to 12 months. It is being used on two 55 gallon tanks,and one 10 gallon.
If you are tired of DIY CO2,and are willing to spend maybe $200 on a good set up,a standard regulator will cost the same as a paintball regulator, and you should only have to fill it once year,rather than once a week.
This one will work fine,and has a solenoid valve,
http://www.amazon.com/Milwaukee-Instruments-Solenoid-Regulator-Counter/dp/B001DTNWF2
Then you will need a bottle,CO2 tubing,and a diffuser.