I was getting tired of using feeler gauges etc to level the TOM stage and picked up a Dial Indicator on eBay
( http://stores.ebay.com/General-Tool-And-Supply-Company ). Then made the dial indicator holder from
http://www.thingiverse.com/thing:13795.

Everything works great, makes leveling a breeze. Now, where to stow the Dial Indicator and clip? Solution, design a mount and clip it behind the extruder while not being used, also adds some weight to the Z stage which helps in operation.

Download, and print it!

Add double sided tape to base and place behind extruder stepper motor.

I used 30% fill but I don't think its critical.

Depending upon the tape you use you might need to add an M3 fastener, just drill a hole in the middle if necessary.