Another possibility is the Rolleiflex SL66. The lens racks out pretty far for 1:2 reproduction, and you can easily reverse the lens (without adapters) for 2:1 reproduction.

In all, it's a nice camera for close-up work. My only suggestion would be to use the camera on a sturdy tripod, as it's a hefty camera.

Plus, there are a decent selection of Carl Zeiss lenses for the SL66.

Here's my brief writeup on the SL66.