Many people are fabricating InTake systems and throttle bodies from various sources of components.
google around a bit: throttle body head runner plenum
http://www.mez.co.uk/megasquirt.html
Mechanically controlled throttle
you can usually find Suzuki GSXR (600,750,1000,1100) throttle-bodies for under 100 Euro on ebay.com, ebay.de
Electronically controlled throttle
Also called as InTake/DriveByWireThrottle
(we don't make a distinction of "drive by cable throttle" )
InTake/ThrottlePlates/VAGElectronicThrottle
See also