Jeff,
There are a number of museums that have built passenger cars trucks to go under their bodies. I think the first was the Colorado Railroad Museum. Then C&TS have built Jackson & Sharp and Pullman type passenger trucks.
The Durango & Silverton tourist railroad has put new trucks under their cars as they build or rebuilt them.
if you hunt around the Internet you should find plans for the narrow gauge trucks. If now the J&S records are at the hagley Museum in Wilmington, Delaware.
Of course the standard gauge are bigger and heavier.
Ted Miles, CRRM Member