+10 points for the logo, I like it a lot.
I tried the "shiny buttons" theme. I'm not sure how much you're limited to changing at the moment, so my criticism might not be worth much. There's a little blurb in the Themes menu in Audacity saying most of the icons won't be changed when using themes. I guess they hadn't implemented everything yet when they released 1.3.3.
Anyway, here goes:
I don't like the lack of contrast between the Track Data Text and the Track Data Background.
I also don't like that the background of the audio tracks is dark. My Selection Tool cursor is black and it makes it impossible to see.
You changed the background color of the About Audacity window to a terrifying green. I cried.
And finally I don't like the gold Slider control. I'm guessing you were trying to change the sliders too, but as it stands the new slider button and the old sliders clash horribly.
On the plus side, the main control buttons look great. I like them better than the original. And the logo looks fantastic.
I'd call this an excellent first pass. Unfortunately the feature isn't yet implemented fully, so it might just have to wait.