MEWS has just published Part 1 of the latest plan by Julius De Waal, which is for a simple spirit fired G3 0-6-0 "Hunslet" type locomotive - with a single-cylinder geared drive arrangement. The plans are downloadable in PDF format and are free for private use.
http://modelengineeringwebsite.com/Hunslet_2.5%22_drawings.html
Regards,
IanT