Types of Keyboard-like Inputs
Operating System Supports - Keyboard settings: Your computer comes with some features built into its keyboard: sticky-keys, repeat rate, hold-time (slow keys), keyboard navigation

MAC OSX/Apple: http://www.apple.com/accessibility/

Win: http://www.microsoft.com/enable/

FireFox: http://www.mozilla.org/access/qa/win-ui-kb-accfunctions.html

Capture keystrokes: http://www.keyghost.com/

Software
WiViK on-screen keyboard
http://www.wivik.com/

MiniKeyboards
Magic Wand:
http://www.magicwandkeyboard.com/
Mini:
http://www.fentek-ind.com/minikb.htm#minikb

Large Keyboards
Key Connection:
http://www.abilityhub.com/keyboard/expanded.htm
USB King:
http://www.aroga.com/com_access/com_products_detail.asp?Item%20ID=8142

Alternative Keyboards: http://www.aroga.com/physical-access/

Hands free Wake up Keyboard http://www.nanopac.com/Wake%20up%20Keyboard.htm

Keyboard Supports

Splints http://www.comfysplints.com

Keycap Labels http://atto.buffalo.edu/registered/ATBasics/AdaptingComputers/SimpleModifications/keyboard.php

Keyboard Trays
http://www.alimed.com/
http://www.datavisionergonomics.com

Touchless Keyboards:
http://www.lightio.com/touchless-keyboard-mini.html