I've got to disagree. Toward the end of his life Joe Pass played solo a lot and used his fingers to play melody chord and bass line. He also sat with the guitar (on a strap) across his body in the same manner as classical guitarists to enable his right hand to access the strings better and to accomodate a more comfortable and practical left hand.
Joe pass took a standard jazz tune or his own composition and arranged it for Jazz guitar using many principals that any polyphonic solo instrument might use such as counterpoint, self accompaniament and so on.
He made use of standard harmonic prinicipals as well as many alternative ideas that were developed by Jazz musicians such as tritone substitution, modalism and polytonality that are now being picked up by Classical composers such as Leo Brouwer and Mark Anthony Turnage.
I know exactly what you are looking for in terms of his music. He produced several solo guitar albums called "Virtuoso", I think there are 3 in total and they were done in (guessing) early 70s and over the next two decades he developed this technique, later to be picked up by Martin Taylor and Tuck Andress et al. Martin Taylor has produced an interesting book where he shows you how to take a standard melody and reharmonise it and add bass lines and interesting rhythmic effects. Played on a classical guitar these pieces would not sound too disimilar to a contemporary classical piece.
If you want some challenging stuff along similar lines look at John Duarte, he has arranged a handful of jazz tunes for solo classical guitar and many of his pieces have a jazz influence. He was a jazz guitarist early in his career apparently. Also Ralph Towner, a jazz guitarist now only makes use of acoustic (mostly classical) guitar and his pieces include complex harmonic and rhythmic devices similar to Brouwer. Badi Assad has performed his pieces (She is a Brazilian multi styled guitarist) and of course Brouwer himself pays his homage to Jazz in his piece "Variations on a theme by Django Reinhardt" (title may be innaccurate).
I also have a suite of pieces by Pierre Lerich, Tombeau de Luys Milan which is a crafty fusion of early rennaisance and harmony derived from jazz.
I think you'll find that the high level of musicianship that most top jazz musicians attain (usually through self development) means that they are being taken seriously by the classical world. Keith Jarret, Bobby Mcferrin and the guy with the trumpet whose name eludes me right now are just several names whose technical achievements have led them into the world of classical performance while Mark Anthony Turnage has written (Avant Garde Classical) music specifically for Jazz musicians such as John Scofield and Peter Erskine.
Want more proof just look at the ECM catalogue for a start.
Gosh I do go on.
Back to Joe Pass. No, not classically trained, but an innovator who is to Jazz guitar what Tarrega was to the classical. Overlook him at your peril.