We were the first year to have a prom at my school (in the upper sixth) - we organised it ourselves, because we wanted a big blow-out - it was the rite of passage thing. Many of us had been at school forever (it was a small town), indeed, even since pre-school in some cases. But it wasn't an over the top, expensive do, because we were doing it ourselves. The most expensive bit was the marquee. (Ah, I remember when it were all school fields round those houses...) Some people did get their hair specially done and so on, but it didn't matter if you didn't, and it didn't matter if you didn't have a partner.
Someone at work this year was talking about their 16yo's prom, and there was a competition to see who could arrive in the most outrageous transport - it's that sort of competitiveness (it's not like putting a few ribbons on the car, it's hiring stretch limos and helicopters) I don't like.
I do totally get the importance of social inclusion, especially when you're 16 or so (and having been one of the ones who has never really been at the centre of things, socially) but it should be the focus on being involved, rather than normality in terms of heterosexual coupledom and the "right" dress and right makeup and right transport.
A quick google about prom charities (to try and remind me of the name, which I still haven't found) show there are quite a few of them, and they're called things like the Glass Slipper Project, Fairy Godmothers Inc, Prom Fairy Foundation, the Princess Project - I feel a lot more twitchy about the values names like that are holding than things like the Prom Project or Dress to Remember, although probably they're all doing something pretty similar. (I'm going to have to look at my meeting minutes tomorrow to see what the name actually was.) Some of them (possibly all of them) do also do tuxes for the boys.
I do think rites of passage should be marked, and I think leaving school is a pretty big deal, but that's the bit to celebrate, not the competitive over-consumption.
I too have been to a black tie do in black tie, mostly on account of not being bothered to find a new dress. It went down a storm - I bet if a bloke had turned up in a ballgown, there's a strong chance he'd have been turned away, even if he looked as good as Grayson Perry at the palace. There's definitely an inequality there.