The Mantua/Tyco Ten Wheeler is really a 64n3.5 locomotive and not HO. It matches a SP 3 footer in Scale64. They can be found at trains shows.
By utilizing the back two drive slots a small 4-4-0 can be developed. The chassis will except up to 19mm diameter drivers without boiler modifications. Shorten the frame and add a two wheel pilot and a mogul can be developed.
Banta Models offered this Sn3 C-16 cab that was the right size for 55n3 locomotives. With minor modifcation they fit the Mantua Boiler. They are nice but will be difficult to find.
YardBird Classic Trains offers this Mantua/Tyco Remotor Kit.
Frames
Bowser's HO Pennsy I-10 Decopod Frame matches the wheel spacings for a 2-8-0 and 4-4-0.