Yes, the timer function is a waste, IMO - the cooldown issue is nearly moot on MB diesels. But yes, as a boost gauge it does look kinda neat:
http://cars.ign.com/articles/384/384396p1.html
http://www.blitz-na.com/Blitz_Products.htm
Not sure if this comes with manual boost sensors, or if it will work on any turbocharged engine. It mentions a wiring harness that is specific to a select group of turbo ricer cars. The data sheet leaves a little to be desired.