I like the idea and I note your explanation of the thread
seeking to explore the relationship Steampunk has with music
It's a question I have often found myself asking and I am not sure there is a clear answer but don't let that worry us at such an early stage. I'll kick off with a suggestion for the bandonéon. This instrument was designed and built as a 'serious' development of the concertina to play concert and religious music as compared with the folk music of the concertina. As such, it gets my vote as it is an attempt at a serious instrument and aspires to the higher realms of art, whilst remaining a relatively simple, understandable instrument. I first came across it in the music of Astilleros, an Argentinian tango orchestra that contributed the musical and comedy background for a local production of 'Romeo and Juliet'. I have posted elsewhere on that, but suffice to say, the band, when 'on show' dressed in waistcoats, bowler hats and although goggles or cogs weren't in evidence, they lent a suitably steamy atmosphere to the performance.
Tango seems also to be quite steampunk in its origins and ethos. The music has a formal structure as far as I can tell and is certainly very showy, containing a real rhythmic passion, dissonant chords which shock, and a tune, often hummable by only the most brave! It is assumed that the music also contains a strong visual element, as evidenced by the band's decision to steam up for the play and the accompanying dance, so full of fire and emotion. Yet, it remains accessable and is not inherently exclusive - it appears to welcome allcomers. So, whilst not being able to provide further in depth analysis, I offer Astillero, the tango and the
bandonéon as an example of what one form of steampunk music could be like and some of the reasons for my thinking.
http://youtu.be/5IR5acIDIsU