Ron,
Like you I'm an even 6 foot with a 30" inseam (God indeed has a wonderful sense of humor, as I also have a 74" wingspan if you will). I have an SWK Wallace Economy and when worn just above the navel, it hits me mid knee.
Prester John on the other hand is several inches shorter than myself, so he is rightly apprehensive I think.
Really the SWK length should not be a huge problem for anyone 5'9" or over, though as some here have stated, they are shorter and it works for them.