Thanks for posting about MyHDL. Actually, it was already mentioned also in your book (p.413).
Some time ago you suggested me to write a "MyHDL Howto" for pldesignline. I made some attempts, but always found the result too "advanced" for an introduction. However, these efforts have been recycled in what now is called the MyHDL Cookbook:
In a few weeks, 0.6 will (finally) be released officially, with the conversion to VHDL. MyHDL should be the ideal platform for language-neutral IP development!