Its a good idea, brass and copper will look well when weathered in.
Only thing that I would suggest ( and only as suggestion for future, its a great work) is to concentrate on some presumed functionality of piece, as at the moment it seems like a random (as pointed out earlier) chaotic gadgetry of a mad scientist, rather than Victorian design of function. Also could do with adding some steam pressure gauges.
Think " would a Victorian gentleman wear this and what for?" thoughts. Unless of course he is a mad inventor, in which case - free run
Thats my understanding of steam punk anyway - it may be different to your thoughts, but I am not a mind reader (felt I had to say it before barrage ensues).
The tighter and slicker you can get the metalwork, the better - it will bring a " wholesome feel" to the piece - in spirit of true steam punk. Its will also help the overall reception of the bust by the viewer.
So - great work - and I cant wait to see next level you can take this to.