Lens Recommendation For More Working Distance

The 75ARD1 has very good working distance. How much are you looking for? As @pepactonius says, there are longer FL bellows lenses available, though image quality is not as good as the 75ARD1.

Note that for longer FL lenses you will also need longer extension.

Let us know the conditions under which you want more WD (magnification/coin size). There may be some lenses that can meet the specific need with as good IQ as the 75ARD1.

Edited to add: are you looking for more WD for more lighting flexibility? There are solutions that help with that.

Further edit: thinking more about this, there are a few lenses which can give similar or better IQ vs the 75ARD1, with longer WD. The Printing-Nikkors come to mind, but they are highly optimized for specific magnification ranges. Ultimately, it seems the best choice may be the 85MV. You'll get a good boost in WD along with improved IQ that is adjustable for CA at any magnification from 0.5 to 2.0. If the 85mm FL does not give you enough WD, then you may need to go with the 105IXL Float lens. I have not evaluated this lens, but I do have a fixed (no CA adjustment) version and it is superb.

Yeah, my main issue is that my standard lighting rig is too low when photographing small coins like dimes on a FF sensor. I can probably do some redesign there.

The printing nikkors seem so optimized for specific magnifications that they seem inflexible.

The macro varon sounds super interesting, and 85mm should give me enough working distance. I just need a bit more. Being able to fix CA at a wide range of magnifications is super cool. I'll try to find one, but they seem to be rare and hard-to-justify expensive.