Great focus and detail, but I just can't help feeling that this would be a great shot in colour and that it's been spoiled just a little by the sepia conversion.
Nice image and sharpness and lighting and tones.
I think for a sepia challenge the subject should fit in with the sepia nature of the shot. Looking at this I can't help but want to see it in colour!
Probably a personal thing. Still though. If that's my only fault with it you're getting a 7.