I'm assuming by "yokes" you are talking about the triple trees. Again, I'm not 100%. Like I said, the only direct "bolt on" that I know of is an entire kx500 front end. As far as I know, pretty much anything else is going to require you to press the steering stem out of the KDX lower triple and press it into the KX lower triple. Further, pretty much any swap is going to require you to have the matching front wheel.
There's a great section at kdxrider.net exclusively for front end / fork upgrades. You might want to check there. There's more information on front end swaps than I could ever relay to you. It would be easier to offer recommendations if we knew what bike you were working on too......
There are other benefits to more modern USD's than just "bling". Rebound adjustment is a wonderful thing.....
J.