Full disclosure: We haven't exactly traipsed around town sampling the services of the city's presumably multitudinous banjo instructors (check the Yellow Pages -- that "multitudinous" bit was a joke), but we have shopped widely for one of the semi-archaic five-stringers to practice on. The level of music-store expertise on display was less than encouraging. We are, however, happy with the picker we found, and his instrumental pedigree is top-notch, so if you find yourself in such a niche market, hie thee to Mr. Anton Ullrich, Houston's self-advertised "Mr. Bluegrass." A Houston native and Kingston Trio-era convert to the instrument, Ullrich has been teaching bluegrass "banjer" since 1972 and has played with everyone from Mance Lipscombe to Merle Travis to Michael Martin Murphy. He spent years spinning a bluegrass show on KPFT, and has the reassuring habit of reminding students that hell, if banjo was so hard, he'd still be a banker. Oh, yeah, and he designed the limited-edition $7,000 "Texas" banjo marketed by the Deering Banjo Company's custom shop. Never mind that he long ago abandoned standard tablature for an idiosyncratic system that looks more like folk art than musical notation. The results so far have been promising. And at $29 for a weekly 45-minute lesson, including a monthly tape dub of bluegrass rarities from his vast collection of out-of-print vinyl, it's a bargain at twice the price.