The rock-n-roll soundstage and all the associated gear completed its long trip home to Reno from California's Orange County. But it won't be sitting idle for long in the industrial building a couple of hundred yards from a runaway at Reno-Tahoe International Airport.Instead, the management team of Karaoke Rockstarz Inc. expects to be training as many as seven bands on the soundstage in preparation for next year's busy season of fairs and festivals. It's an ambitious plan for the company, which had three bands on the road at the peak of last summer's season.Working from a list of about 220 …