During my time at Spike (http://spikehq.com) my team and I worked on a guide to Email Marketing, outlining the best practices, advantages and limitations of HTML emails. I worked on some of the copy and all of the design work, with some very helpful feedback from the team.

 

We sent it to a number of our clients and was very well received.

 

Some pages are shown below.

 

P.S. It has 26 pages!