Niel,

You need to stop thinking sprinkler and start thinking industrial. There are plenty on the market, here is a link with every valve manufacturer under the sun [Link: gateway-supply.com] Be aware good valves or plumbing products cost a heck of a lot more than sprinkler parts. If I were filling my tub by phone I don't think I would want to chance going cheap.

Bill
www.homeautomationnet.com