Pages and sites I've found that help inspire me:
Miniature construction world
http://www.miniature-construction-world.co.uk/index.html
Jibup's Flickr photo stream
http://www.flickr.com/photos/62532775@N03/
Special offroad vehicles
http://www.unusuallocomotion.com/
Leonardo3
http://www.leonardo3.net/leonardo/machines_eng.php
Technicbricks blog
http://technicbricks.blogspot.co.uk/
Tractors home
http://www.tractorshome.com/de/index.php