Somehow, in these scattered postings about orchestration, I have neglected to mention a pair of musicians doing important work on the music-technical and economic/social/political problems of making music with large ensembles.
The first is composer Daniel Goode, who has a long working relationship to the Gamelan Son of Lion (see this posting on Our Other Orchestra) and additionally has, in recent years, worked with both the concept and concrete examples of a "Flexible Orchestra", a mixed ensemble including at least one instrument in multiple instances (in a recent concert, the orchestra was composed of eleven flutes, tuba, harpsichord, trumpet, and contrabass). Such combinations have the potential to provide very striking environments for music-making, in this case including timbral and registral variety but also allowing for at least one example of the symphonic qualities or chorus-effect made available by a single timbre in mass, an efficient and even elegant distilling of some of the most characteristic features of traditional orchestral ensembles. Mr Goode's homepage includes several articles exploring these topics (see especially the "Letter from Vienna" and "How can the orchestra be more like the gamelan?".)
The second example is composer Andrew Culver's proposals for an "anarchic philharmonic". The first concern is obviously the institution of the "obligato conductor", but the standard composition, organization, rehearsal method, and concert structure are all rich areas for exploring alternatives. Needless to say — and precisely because I'm familiar with the pitfalls of previous experiments in this direction (Cage's orchestral version of Cheap Imitation being the central case in point, and Etcetera and some of the Number Pieces indicating some possible paths out) — I'm in complete agreement with Culver. I can't wait to see a black flag flying oover Disney Hall or the Concertgebouw.