Well, about the icons, that's right, the icons come from Elementary, appart from the mail icon, wich is the Evolution's default one, I actually do not like the one from Elementary. The camera also comes from Elementary, but the backgrounds colors apparently prevent us from seing its tango-ish strokes, making it a bit more photorealistic.
For the panel, I do think it should be more simple. The icons' being monochrome allows them to draw attention when becoming red, blue or whatever. To get notified, it's easier to notice that an icon just got some colors...
Indeed this looks quite mac-ish. I agree with you about the menubar, though it saves place, it is not as usable as they say. There is no menubar on my mockup, because I would prefer it to be in a dropmenu in the toolbar.
Lasselongo's idea could be an awesome alternative to a dropmenu.
Do you find my theme mockup features too much shadows and effects ?
And I have to disagree about the dock, because its size can be changed.
Also, I don't know about the others, but I'm not trying to make my desktop look like OSX or Windows, neither I'm trying to make it look like a linux desktop.
I want my desktop to look good and usable. It seems as if my imagination is not wide enough to produce something much different from what already exists, but that's definitely not what's intended