John,
I found a place in our area that does beverage grade CO2 refilling while you wait. If I ever get around to setting up my reactor, that's where I'll be bringing my bottle to each time.
The place is primarily a fire protection shop. If you're looking for a place to just refill, try these guys in Palo Alto:
http://www.acefireinc.com/index.htm
I bet they do the Hydrostatic Testing, too.
HTH
Karl