I think Karamba is better as a seperate program. I never used Karamba, but what I know of it, is that it provides extra graphical things to the desktop. It seems to be a great way to improve the look of the desktop, but I can imagine that this comes with the price of the reduce of speed, espessially on "slow" systems.
Personally, I allmost never see the desktop. I have all my windows maximized, and I use seperate desktops for seperate programs. If a program like ksensors is set on the desktop, I will never see it back.
There seems to be
plans to make an autohide system to make the system tray more functional.
The system tray is an applet. Maybe, it can be made possible to add applets to Karamba. That way, it is possible to set the system tray on any place on a desktop. But I don't know how difficult this is, and what the security risks are.