You can download the skeleton here:
http://hg.tangent.org/skeleton-mysql-engine?ca=tip;type=gz
The skeleton is a "one stop startup" for creating a storage engine under MySQL. It has all of the moving parts for an autoconf project setup for you and it includes the example engine to play with. This is not an official project at MySQL just a nice have for people who are interested in getting up and running with a new storage engine quickly.
Calvin is looking at adding support for Windows for plugin builds so that Windows developers can quickly come up to speed in developing engines.
It will make Microsoft's job a bit easier when they port SQL Server's engine to run under MySQL :)