My new macro setup gets me 7.8x magnification (3mm fills the frame vs 23mm with normal 1:1 macro). Mostly made of parts from eBay I have accumulated over the years. It starts with a manual 50mm f4 EL-Nikkor Enlarging Lens which is about 1 inch long.
The rest adds up to 16 ¼ inches at maximum extension. 50mm of M42 extension tubes. Two M42 Helicoids, 15-26mm and 36-90mm. Then an M42 Asahi Pentax Bellows II. M42 to A Mount converter. 69mm set of Vivitar Extension tubes. Sony SLT-A57 camera. Wired remote. The flash is a Sony HVL-F58AM on a Dynax bracket with a mini ball head. All of that on a 4-way Macro Focusing Rail Slider and Manfroto MK394-H tripod. It is nearly unusable, extremely difficult to aim and focus. It shakes a lot even using the remote.
Other than the tripod, everything weighs about 7.5 pounds. A heavier duty tripod and rails would probably help but I don't need this much magnification. I just wanted to see how long I could get. I was really surprised that I still had 1 ¾ inch of working distance.
Since taking this shot, not even half those parts have been on the camera at the same time again. But it made a fun picture.