This is something I think through a lot. I think cost is the main issue, as stated before.
I had a deal in the works recently for a Leatherman Wave, and the owner had a custom S30V blade made, that he said cost as much as the tool. The cost of that kind of shocked me.
A.G. Russell made a 'Premium Scout Knife' with a better (154CM?) blade steel, but the tools remained something like 420, as it was better for the purposes the tools served. It occurred to me that that might be an issue as well, having to use different steels - and different manufacturing techniques and more production time - for various implements, again driving costs up.
I'd love to see a beefy, G10 handled TL29 in D2, or a Remington replica Scout in the same material. Maybe see if one of the new manufacturers (Canal Street!) would be willing to make a cool BFC annual knife for us, to our specs.
There are several tutorials online on taking down SAK's, and rebuilding them with different tools. I always wanted an ALOX model (Soldier?) with scissors, but I read somewhere that ALOX types usually don't have scissors, and the scissors from the celidor types won't interchange due to the spring configuration. Other than that I've seen some pretty nifty SAK mods.
That's what makes being knife knuts so much fun: fantasizing.
~Chris