Hmm, according to the specs a medium still has a top tube length of 22.6" which is about the same as my Kona isn't it? Standover is given as 28.9 for medium and 29.8 for a large. Is this measured as literally the top of the top tube to the ground or from some point a certain amount above the top tube? Haven't found accurate geometry details for my Kona, the nearest I've found is for the 2005 Explosif...
Try konaretro.com Geoff. Unfortunately he never got the 95 or 96 catalogues on there, but the 94 geometry is the same as 95 - incidentally I was wrong in an earlier post, it was actually in 1994 that they made the bikes a half inch longer, so there's no point in you seeking out a more recent Kona.
As far as 22.6 is concerned, that's shorter than a size 18 Kona - Kona quote the 18 as having a 23 tt and the 19 as 23.5. My Kilauea (97) is a 17 and it is actually slightly longer than the quoted 22.5, so I'd say that a medium Bonty is about as long as my bike (but way higher!)
Measuring standover is a bit of a black art, but it's often given as the height of the mid point of the top tube.