Stealth Audio used to sell a locking IEC. Contact Serguei at: stealth@stealthaudiocables.com
The tightest fitting regular IEC I've used is a Furutech FI20. You can actually pick up a piece of equipment by the PC & it won't let go. I did it with a lightweight CDP but wouldn't want to try with my 55 lb. amp.
Richard, I've added IEC jacks using a dremel tool. I use the dremel for lots of projects but wouldn't buy one just to cut out one IEC. You can purchase IEC jacks from Michael Percy Audio for not much $$$. I've added bigger captive power cords to several pieces, the biggest project being some mono-blocks, which involved drilling out the PCB. I purchased strain relief's from Michael Percy and had to drill a 7/8" hole to fit the strain relief.
It should be a pretty straightforward soldering job to replace the existing PC on the Kenwood and you can even use the equipped strain relief with a bigger diameter PC by drilling it out.