I really hate to say it man, but I doubt you'll get anyone at that price.
Few people really have any reason to change clusters unless they really want a tach; but you can pick those clusters up off Ebay for 1/3 or at a junkyard for 1/2 of what you want for yours.
Granted, yours are brand spankin' new, but it's not like a cluster really wears out or anything.
Add in that they're kind of an 'unconventional' 150mph cluster, and that most people who want a tach probably want it for aesthetic reasons and therefore also probably want indiglo overlays or faces which are harder and more expensive to come by for 150mph clusters....
