are there any decent-sized open source projects using eclipse EMF and ecore?

Question

that have source code available?

and follow good EMF recommended design principles.

Answer 1

Absolutely:

• The GMF project of Eclipse uses EMF extensively.
• The UML modelling project of Eclipse uses EMF + GMF.
• The implementation of XSD in Eclipse is also provided with an EMF implementation.

There are dozens, if not hundreds, of other open source projects with source code available that rely on EMF. One of my projects, IAML, is one of them.