Annette,
I could only find one Davis treadle in a quick search of Seattle CL:
http://seattle.craigslist.org/kit/fuo/5104260960.html
This will fit the Davis VF models VF2 and NVF though they may not drop down due to clamping system of head. I'm a little suspicious that the head is not attached to the cabinet so it would need a close inspection.
The White irons will also work fine.
Jon