About the only thing that i can think of, that really offers what you want would be a Mac Mini with all your music ripped in Lossless, and fed into an AirPort Extreme set-up, with powered speakers. You can use an iPad or iPhone with Remote on it, which gives you the ability to scan through all your music in album art format, or artist or title list format.
I never use album art, because large amounts of my music is ripped from the sample CD’s that Uncut and The Word magazines give away, so that’s several thousand tracks that don’t have metadata to allow original album art to be sourced, and I really can’t be arsed to source each one individually.
I rip all mine at 320Kb, rather than Lossless, because of space considerations on my iPod, and, quite frankly, I can’t hear any difference between 320Kb and either Lossless or FLACK, when I’ve done a comparison.