This set-up is for pinned insects but could be used for any small subject that will tolerate being held in a vertical plane. I find that using the camera in a vertical plane gives me a pain in the neck.
Canon has the edge on Nikon when it comes to Macro photography. Jay's MP-E 65mm lens has a magnification range of 1X to 5X, compared to Nikon's Micro lenses that go up to only 1X.

Nikon D70
Nikon 105 mm AF Micro Nikkor + Nikon 4T supplementary lens. Combination gives a 2X magnification based on standard 35 mm frame (most magnification needed to fill the frame with a Horse Fly head)
Lens shade

Camera body mounted on a RRS CB End-Rail (allows for coarse vertical adjustment)
CB End-Rail attached to RRS Camera Bar
Camera Bar bolted to plywood box on table top so that camera is at eye level. Bar can be tripod-mounted.

2 Nikon wireless SB R-200 flashes mounted on RRS Flash Bracket
(flahes triggered by camera's built-in flash)
Flash Bracket on RRS Multi-Purpose Rail mounted onto RRS Mini Clamp that slides
along the Camera Bar. (Top set of Mini Clamps is for support of a Nikon PN11 extension tube for further magnification). With a PN11 extension tube between the camera body and the lens both the camera body and the lens are clamped onto the Camera Bar allowing for a very stable set-up.

Pinned subject on foam-covered bracket attached to a Velbon Focussing Rail (for fine vertical and horizontal adjustment). A bracket connects the above to a Kirk Focussing Rail for forward/backward fine adjustment. This focussing rail on a Mini Clamp that slides along the camera bar.