Well, I'm preparing to run a cloak sewing workshop for the Order of the Golden Lion two weekends from now. Looks like I'll be making my own cloak sooner than I'd expected. The basic pattern we intend to use is here:
The Pres. tried this pattern and has a gorgeous cloak. She had to make a few huge changes though. For one, the neck hole should not be semicircular. It should be moved back to be more of a complete circle. This keeps the cloak from choking you. Secondly, the hood provided with this cape is totally ineffective. I'm going to try to find a new hood pattern for my group.
I read "What Fabric Should I Use?" and "Colors for Lower-Class Elizabethan Clothing" here: http://www.elizabethancostume.net/
Since we actually spend a fair amount of time outside, we're all leaning toward wool cloaks for warmth. Some of the group members are also talking about lining their cloaks with satin, cotton, or a blend. One guy wants a reversible cloak. Some of us will be hemming the edges, while others intend to use seam binding.
As far as clasps go, I think most of us are planning on sewing on frogs. The dude with the reversible cloak will be sewing a cord into the neck that can be tied. This lets the cloak be totally reversible. Also convenient if anyone ever gets annoyed with him :)
I shall post a hood pattern when I get one. This whole project is going to be very fly-by-the-seat-of-the-pants. Sure, I can teach 10 people to sew at the same time while keeping track of 4 different machines! It shall be a true adventure!