Links to keyboard encoders

List of keyboard encoders
http://wiki.arcadecontrols.com/wiki/Keyboard_Encoders

KE USB 24 Keyboard Encoder Module
http://www.hagstromelectronics.com/products/ke_usb24.html

Keyboard Encoder Modules
http://www.hagstromelectronics.com/products/modules.html

IPAC1
http://www.ultimarc.com/ipac1.html

audon.co.uk encoder
http://www.audon.co.uk/kbe-629.html

Vetra "SmartWye" Series PC Keyboard Encoders
http://www.vetra.com/Encoder2.htm#anchor660364

Vetra "SmartWye" VIP-312
http://www.vetra.com/312txt.html

KeyWiz Eco 2
http://groovygamegear.com/webstore/index.php?main_page=product_info&cPath=76_80&products_id=200

KeyWiz Max 1.5
http://groovygamegear.com/webstore/index.php?main_page=product_info&products_id=199

X-Keys matrix board
http://www.xkeys.com/custom/xkmatrix.php