Thank you for your help. I eventually achieved this with LordHavoc's sv_user.qc.
I have another question though; how would I find out whether the player is running (using +speed) or not via the QC. Is there an easy way to do this or am I going to have to go to the trouble of learning CSQC (CSQC_ConsoleCommand?) or making my own run button via impulse commands?