I think your results are quite nice, and I stopped by the rest of your website and found many interesting images. If you consider photography a "playground" for interesting techniques to explore different visions I think you'd find you like MFDBs quite a bit - there are many unusual bodies, lenses, accessories, and techniques allowed due to it's highly modular nature.
But if you're looking for something a bit more plug-and-play then an entry level digital back with a Phase One 120mm D Macro with two extension tubes would be a good place to start. If you're in the US we'd be glad to help arrange the appropriate testing. The
Credo 60 right now is on promo with a free body/lens. We could probably work something out to switch the 80LS to a 120D Macro; or you could look at some of the older generation macro lenses. The Mamiya 120mm non-D macro is a very very good lens and can be found for a bargain used. The even older Mamiya 120mm Macro for the 645TL (still fully compatible with the newer bodies - with the obvious limitation of having to manually control the aperture) is even less expensive and still quite good.
If you want to be free to experiment with more combinations of approaches/equipment then I'd suggest a body that has a focal plane, like the Phase One DF+, which can therefore use random/off-system lenses. I'd also suggest a modular digital back system so that, if you need to, you can remove the back from that body and put it onto another system. Even a homemade plastic body with a Leica Photar or enlarging lens could give you good results (albeit with less precision and ease of use).
Remember that with more pixels you're effectively adding a "TC" to the absolute detail recorded while maintaining the angle of view of the non-TC image. The fly image I posted looks even better as a large print where the detail of the 60mp original raw files can shine.
