A mini CW key by PY2OHH
We show here the project of a CW key where 90% is mechanical construction and 10% electronics (two solder junctions).
http://py2ohh.w2c.com.br/trx/cwkey/cwkey.htm

Converted-Mouse Paddle with a built-in Keyer by 7N3WVM
The built-in keyer is also homebrewed from scratch. ... I usually operate this paddle with the thumb and forefinger as is shown in the picture at the bottom.
http://www.qsl.net/7n3wvm/keyer-mouse.html

CW keyer for foxes and beacons by PA3HCM
Beacons and foxes have to identify themselves. Although I could sit along all day with my morse key, transmitting my call, I wanted to have some automatic keyer.
http://www.pa3hcm.nl/?p=296#more-296

Homebrew CW Paddles by AA5TB
I had long been needing a set of paddles for use during and field operations. In my junk box I had a switchcraft panel switch that had leaves that could be disassembled and I had thought of using it to make a set of paddles ...
http://www.aa5tb.com/paddles.html

Homebrew Paddles by LA6AKA
Here is a set of lo-tech morse code paddles that I built during a couple of days between Christmas and New Year. Don't build them yourself! They turned out to be really cruddy.
http://arj.nvg.org/ham/paddle1.html

Homebrew Paddle with a built-in Keyer by 7N3WVM
The built-in keyer is also homebrewed from scratch. ... The rest of the space is filled with a batch of lead sheets for the anchor. A careful watcher may find that LEGO blocks are used for the knobs.
http://www.qsl.net/7n3wvm/keyer-lego.html

NB6M Paddles by NB6M
The best part about these paddles is that you can make them yourself in just a couple of hours or so, start to finish. They are made from readily available materials, and cost almost nothing to build.
http://www.amqrp.org/projects/paddle/NB6M Paddles.html

Double Lever Paddle by PAØCMU
Wayne Mc Fee, NB6M created a simple and easy to build CW paddle made from PC-board. Using Wayne's idea as a foundation I designed a double lever version for iambic keying.
http://members.ziggo.nl/cmulder/paddle.htm