Has anyone used this keyboard:
Logitech wireless solar keyboard k750

Does it work in linux? any linux?
Multimedia keys? etc...

The fact that it is wireless, and solar-powered, doesn't matter.

It connects to your PC with a USB dongle, and I expect it will appear as a USB keyboard, in the same way as my wireless logitech mouse appears as a USB mouse.

I cannot advise you about special "multimedia" keys, but these are not usually difficult to configure manually in the event that you do not find they work from the moment you plug it in.

I have yet to see anything made by logitech that did not "just work" with linux, but I cannot guarantee that this device will not prove to be an exception. If I thought I needed one, I'd just go and buy it.

Please let us know how you get on.

Setup was straight forward: plug in the USB nano receiver and turn the switch on.

I have been using the K750 on Ubuntu 10.10 and 11.04 without issue. the "FN"(or multimedia) keys all seem to work correctly (when on the desktop) except for keys F5-F8. F12 put my computer in standby not shutdown, but as tredegar stated this can be changed. Keyboard feels very sturdy for something so thin!