For years, I struggled to find a system that allowed me to store finished bike framesets around my shop without the forks clanging around in the headtubes. Finally, I decided to make my own dummy headset.
This product is two parts: one upper and one lower section of a dummy headset. It can be used to securely hold a 1.125" threadless fork in a frame. The upper part has two holes "drilled" into it. Their diameters are 3.3mm, which allows them to be hand tapped for M4 set screws or thumb screws. I recommend using McMaster-Carr 90418A229 (brass tipped) for steel or aluminum steerers, and 93285A212 (nylon tipped) for carbon fiber steerers. More info here: http://pencerw.com/feed/?tag=noheadset