Before I could share information on the forum, within a day of posting the findings on my site, the objective sold out. After some time with the original still out of stock, and with the help of another PM.net member we found very similar barreled 4X from an Ebay seller in China, but it was not the same objective.
But the good news is that the original 4X Plan Achromat is back in stock!
So now that you can actually buy one, here is an image, un-cropped, from a full frame Nikon D810. Handheld 5 image stack, single nikon SB-R200 flash. Zerene Stacked DMap.

100% crop. Not record setting sharpness but pretty good!

Nikon D500 this time at 4X, 5 image stack, single flash, tripod. Stacked in Zerene using Dmap.

100% center crop, D500.

Extreme corner crop on D500. Sharpness looks very consistent corner to corner on an APS-C sensor.

The lens is a finite design and really compact so its is easy to use, plus the nose cone comes off for an even smaller profile and more WD.
There is an image quality drop in the corners as you would expect but not as much as you would think. I'm impressed.
Great coverage, look at the pencil image made with my D810! That shocked me more than anything.
CAs are very well controlled and a lot better than more expensive objectives.
Sharpness is not bad at all!
This is an easy buy for someone that wants something that performs well at 4X and doesn't cost a whole lot of money!
When I get some time I plan to compare this to some other 4X objectives that I own when I get some time like my Nikon CFI 4X 0.1, Nikon BE Plan 4X, and CFI 4X 0.13, and CFI E plan 4X, just for fun, it should be interesting.
Objective

The sellers site:

Link for the above:
http://www.amscope.com/accessories/obje ... ens-1.html
Link for an ebay seller with the correct objective: http://www.ebay.com/itm/381613828736
Quick Objective specs from the sellers site:
This is a 4X DIN-standard objective lens for compound microscopes. It features achromatic color-correction, and plan field-correction.
Magnification: 4X
NA: 0.10
Tube Length: 160mm
Cover Glass Thickness: 0.17mm
Brand Name: AmScope Model No: PA4XK-V300
Magnification: 4X
NA: .10
Optical Working Distance: 29.04mm
Thread: RMS
Mechanical Tube Length: 160mm
Cover Glass Thickness:0.17mm
Color Correction: achromatic
Field Correction: plan
Immersion Medium: none
Nosecone: fixed
Note that the nosecone is not fixed but it is removable so you will gain a couple of mm working distance with it off.
Link to my new site with some more images made with this objective:
https://www.closeuphotography.com/seven ... -objective
Comments and questions welcome.
Thanks for looking.
Robert