Well you are obviously not thinking properly with your pre-occupation with your DSLRs ... they may sell well to the general public and need the larger sensor for that, maybe, but are hardly anything special in photographic circles.
As you said yourself earlier in this thread it is easier using a DSLR.
Grahame ... shooting macro or 1:1 or double extension is precisely that .... back in the fifties I used that knowledge to work out the focal length of a lens. It is convienient to use a close-up lens on a longer lens to overcome its inability to focus close, really the only option with a fixed lens camera where it is widely used, but when we talk about ILCs with the lens and camera separate entities it is merely a question of how you arrange extension .... when copying part of a 16mm film frame [7<8mm subject onto 35mm film which is 36mm wide] I used an extension tube-set on the camera and another on the lens and coupled them together with a short length of plastic tube ... working in my darkened basement so light leaks were of minimal effect ... I call that lateral thinking by somebody not hamstrung with what Canikon provide. Later when I had a bellows I used the 25mm lens from my Bolex movie camera to achieve x9 magnfication with the same camera 4mm of subject filling the 36mm wide negative.
Here using just a 50mm for less magnification ...
The longer the lens the more extension required ...but the longer the lense the more room you have for lighting though here as often I shoot by available light.
With my home made mounting to protect the Nikon lens from the weight of the 50mm lens. I forget but the file number suggests I used the Canon s20 P&S to photograph the Nikon Coolpix 5700Though it might have been the D60.
In fact it wasn't until the digital age that I had either a Canon or Nikon camera ... they maybe the herrings of the photo world but not the only potential catch by any means.