Welcome awhale,
There are lots of things to make at John-Tom:
http://www.john-tom.comYou can scale them up or down if you like the challenge of doing that.
Are you interested in more than steam? Some members here try to make not only steam engines, but heat engines, Internal Combustion Engines, Turbines, and Solenoid Engines.
Also, if you hang out on this and similar forums, you see that many get involved with building tools and attachments for their lathes and mills. There are also those who build mechanical devices for their engines to power so that they "do something." (Brian Rupnow is one such person.)
All in all, once you start making things you will find that the list of things you want to build will get longer and longer ...
Don't be afraid to post your experiences as well as your end results: We Like Pictures.
ShopShoe