Forward Multiple Messages in One with Mac OS X Mail

If I can pack dozens of emails in one forward with admirable ease in Mac OS X Mail, I sure can pack the laptop, the running shoes, the hiking boots, the shampoo, the hair dryer, the toothpaste, the shirts, the... in this bag. It. must. be. possible.
Forward many, send just one! Here's how to combine multiple messages to one forward in Mac OS X Mail.