Mvix on Thursday launched an ultra-compact HDD-based, portable media player: the hi-def new Mvix MV-2500U media decoder supports the small 2.5-inch hard drive, while including key features of its predecessors like MX-780HD or MX-760. The black device, which can support HDDs as large as 250GB, measures under 5x3x0.5 inches; it uses a 2.5-inch PATA /