jessica's right, there is a recording of the ballet mécanique on the budget-priced naxos label (god bless 'em, ever an indication that price is no guarantee of quality. for a budget label a lot of the their catalog blows the full-priced labels away.) for some reason i've never felt compelled to buy a recording of this piece tho, i dunno why. perhaps a misconception that the work, like that of e.e. cummings, was gimmicky or something.
i'm curious too about antheil's treatise on harmony and ezra pound's book on same. what i'm reading on pound lately suggests that antheil was something of a flash in the pan, that he never fully lived up to his early promise. (tho he did write some violin sonatas for pound's lover olga rudge.) which is another way of saying again he was ahead of his time. tom raworth said he'd recently read somewhere online that some guy at MIT only just figured out how to rig the 16 baby grands and all the other instruments up to play together electronically a few years ago. (hopefully tom'll send me the link!)
i'm kinda surprised more composers have not explored this further. actually it's no surprise given what sure must be the exorbitant cost. i'd love to have been the person at the NGA who called up some piano dealer and said "hello, i'd like to rent 16 baby grand pianos for a month." seriously tho, imagine what steve reich could do with that. or someone like ben johnston who works in just intonation or microtunings!
further pound squad update: as i emailed ben last week, the finding aid for the beinecke library's pound collection lists 492 folders with radio speeches. this does not mean 492 discrete speeches as some are undoubtedly duplicates. there's also a folder titled "300 radiodiscorzi" (sounds so much better in italian), possibly a table of contents for an italian edition that pound wanted to publish. in any case, the 105 speeches doob printed in ezra pound speaking are likely only 1/3 or less of the total extant radio speeches.