"kded4 -v" does it for me.
"kdesktop -v" also gives a similar output, but I'm still running kde3, so it only shows the running 3.59. I don't know if it will show kde4 output, or whether there's a different command for it (there's a separate kded for kde3).
Edit: It looks like every kde application shows this. I only have a couple of kde4 programs installed (ktorrent has moved completely to kde4, for example), so I get different outputs depending on which version the application is based on.
Last edited by David the H.; 01-11-2009 at 04:00 AM.