Whilst not strictly steampunk, posting the info here in case its of interest to others (the event is nothing to do with me, other than being an enthusiastic attendee!). One of the "tribes" for this post-apocalyptic themed ball could be vaguely construed as steampunk but with a twist.

Aftermath - The Apocalypse Ball
Salisbury Arts Centre
Saturday 12th June 7.30pm - 1am
http://www.darklightindustries.co.uk/Having been to the previous years' Balls in Salisbury, I can thoroughly recommend it as a fun night out. Sounds like there are going to be some imaginative costumes for this years' too!
Have bought all the componants to create my post-apocalyptic ballgown, now just trying to work out what to do for a mask (some form of customised goggles maybe?)