Regarding the clad, as KMN said, steels are often clad to reduce cost and offer corrosion or brittleness protection where applicable.
One of our upcoming Mule Team's is a high Cobalt special made by Takefu and it's going to be clad.
We'll generally go with what the maker can get and work with. Getting some of these steels has been a challenge. We generally want smaller quantities to make a Mule run and it's less than they like to sell. It's been a "Spyderco who" wants what?
It's getting better lately as some of the foundries have heard of our Mule Team project and they are beginning to offer smaller quantities. My sales pitch is that we'll get their steel out into the market where it may catch the eye of potential customers. Now the problem is too many steels and at 4 per year, it could take many years to get the particular steel someone might want. That's why many of the new steels will be offered in knives as well as Mule Teams.
As far as the Caly 3.5, that was aimed at the Mastiff. He's been a fellow steel-head for many years. We have similar tastes in daily carry knives. I carry a Caly 3.5 a fair amount. It's a good size, ergonomic and easy to carry. I would personally like one in Super Blue.
Murray Carter first turned me on to Super Blue many years ago and I've been itching for a reason to try some in a carry knife.
Hitachi has always been exceptional in their blade steels and Super blue is right in there. It's a "nice" steel. Gets very sharp, like 52100. Feels kinda "old school".
sal