Through the past year a trend has started that is increasing monthly.
Several of the knife makers who are regular customers have been having their customers pick out & purchase their handle material from my web store instead of settling on one of the pieces that the maker has available.
That's a great point, I myself have done this several times with stabilized woods over the past year and it has mostly worked out very well. Further, I've been able to take a drawing in Inkscape of a knife that I'm designing and custom fill the handle with any specific block of wood pictured at a purveyor's site. Then the customer can see roughly what the knife will look like with that block. This also works with damascus and hamons fairly well, I use pictures of blades I've made or pics I otherwise have and make custom fills out of them, then mock up my knife designs with them. But I digress.
I like that I can have a customer pick out and pay for a block to be shipped to me. Takes a little work out of my hands. And, I feel (as do they) that it's a more truly "custom" experience.
We all know that Mark has an excellent range of nice woods, I've done this so far with AKS, though. It is only a matter of time until I finally buy some mallee or gidgee from Mark, though. I love that stuff.
Greg, that's an interesting idea. To me it seems that most of your verticals are going to be categories of consumer that each use a fairly limited style of knife, limiting horizontals for each category. I know that kitchen, for instance, has a huge range of blade styles, but there is a limited range of materials that I would consider suitable for a kitchen environment. Within that range, it's up to the taste (npi) of the cook what to use.
It works better for me to make the vertical into types of knife (hunting, kitchen, throwing, etc) and make the horizontals into materials and styles. That way I can express a range of variables in kitchen knives, for instance.
Or maybe, I can express horizontals as types of user within the vertical category. For instance, kitchen subcategories would be small restaurant, high volume restaurant, food industries, dedicated amateur, negligent home cook. For each of these I come up with a different range of materials and even style.
For collectors though, I find it hard to predict what a hypothetical "collector" will even prefer to own. Some collect folders, some bowies. Each collector will prefer a unique set materials and styles. It would take a far more experienced and intelligent knifemaker than myself to create a system that would adequately predict the tastes of collectors.
My advice is to make what you want, Patrice. As it seems that you are wondering about knives that you will be building on spec, rather than orders. Hopefully a true collector will be interested in your work because of your unique sensibilities and skills, as well as choice in materials. I think that agrees well with what Nick said above, too. If you follow too closely what market tastes dictate, you may end up cramping your own style and you definitely won't be pushing the envelope. And that would be a shame, since you definitely strike me as a maker who could.