AG,
There are two knives that I really like and would like to see some hybrid of. Kershaw's Ken Onions (or at least liner lock) and Queen's Oar Carver. I love Wharncliffes, one handedness and bone handles that fit in the hand like a Flexcut knife. (Yes, I am a compulsive whittler)
Spyderco Kiwi is close, but a bit small. Kershaw Centofante (14xx)has the shape, the action, but not the handle circumference. The Queen carver is a slip joint, which can be a little freaky when you whittle in ways that the Boy Scout manual discourages. A single blade suits me fine.
Steel? One of the "moderns" so the knife can do things beside whittle. Something that can be thin enough to whittle well, but tough enough for general use. You know what that is better than I, if it's an old school steel that's more than OK.