Yes, I do have, and I have used, one of the plastic molded Dot Line Corporation two way levels that mount on the flash shoe. This is mainly for a way to check that things are level when using the camera on a small travel tripod or clamp mount and trying to take a series of shots for a panorama. If I am at home or I have the big tripod and head with me, the tripod, the head, and the panorama click-stop adapter all have levels to use.
Ralph Latte Land, Washington
Nikon F and F2; Nikkormat/Nikomat FT, FTb, FTn, FT2 Some Pre-AI, AI'ed, and AI lenses from 24mmm to 300mm And The 1960s Nikon Project
The best Bubble/Spirit Level that I have found out there was made by Voigtlander. Introduced September 2000, picture on Camera Quest web site under accessories. Getting kind of rare now.I have two. cameraquest.com