'I just love how the Europeans challenge the shape of the ukulele. This one looks very old fashioned and yet modern.' .........there's a simple reason for that!
The machete from Madeira, tuned DGBD, was transformed into the soprano uke, tuned GCEA after its arrival in Hawaii.
This instrument has the appearance of a machete, and since Gregor is calling this a uke, I reckon he must have tuned it accordingly.
Look at his website: there are some beautiful instruments ( with video/sound samples).