A very commendable article in NY Times by Anne Midgette: For Downtown Clubs, the Uptown Classical. Here, she explores the idea of finding the right audience for modern classical music by presenting it outside the usual venues. If you're trying to incorporate a younger audience, that's a good, worthwhile idea but I think it might not go far enough.
Part of the problem is that if you have a classical night at a non-classical club, you're going to usually only draw a certain type of crowd that's pre-disposed to that type of music. That holds true for any style of music. Once it's indie rock night, you'll get almost all a different crowd after that. The question then is how do you draw from other audiences and have them attend classical shows.
I think that Sonic Youth had a good solution to that. During the 90's, they would still share the bill with indie bands for their live shows but they also had a lot of jazz players open for them too. They were clearly fans and did a commendable thing by trying to open up their audience to other styles (especially ones that influenced SY itself).
If you had one of two say, indie bands with some name recognition on a bill along with a modern classical composer, some of the crowd wouldn't get it and go and hide at the bar but there's bound to be some of the audience who "get it" and appreciate it. Not that this will get any particular composer on the Billboard charts but I think it's a workable idea that should be explored more.