There are actually quite a number of surviving street dummies or steam street motors however, in their second life, most lost their original bodies for more traditional looking locomotive cabs.
http://www.internationalsteam.co.uk/trams/steamtram02.htm
This page implies the Annex Creek Power Plant (Berner's Bay Mining & Milling) was a steam dummy which I think this is incorrect.
What were they like inside? I'm guessing there was only space for the engineer and possibly fireman.
This question is more for Dave Grandt. What was the basis for this Porter model?
http://www.grandtline.com/products/images/quarter_inch/kits/93067_steam_dummy.jpg
Dave