I see on the Large Scale board a request for a class A Climax. One would be nice in ON30 as well, although I would not expect it to appear until after a Heisler (a Heisler has already been made in Large Scale). Still one can hope for both.
Hamish
Doing a Class A would be neat, and not too hard to do since the mech is close to what's inside the 45-tonner. I wonder about it's marketability, however, since most the "mass" market has no idea what a Class A Climax is. At first blush, it doesn't even really look like a steam loco. But I agree, Heisler first!
Here is a good example of a class A.
http://www.gearedsteam.com/climax/images/rigbee_&_hugh.jpg