I own a glass-lens square-format Holga that I've retrofitted to take 35mm film in a 3:1 panorama mode. (It normally takes 6cmx6cm or 6cmx4.5cm images on 120-format film.) I also own and use a 120-format Holga that can take 6cmx9cm and 6cmx12cm medium-format panoramic images using a pinhole 'lens' Both of these are fun to use - so buy one and use it already!
However, to date, there've been no cheap, weird-lens, 'digital' Holgas. The site linked into the title of this post discusses making an open-source Holga.D Take a gander and submit your own input. Get involved! Let's make this happen!