Well it's announced, the g100s successor

Preorder available and ships Sept 10.
Main features
-g100s shape
-3366 sensor
-g303 type buttons
-83g without cable
-Kaihl mechanical encoder instead of the usual optical for mousewheel
Height: ~ 35 mm
Width: ~ 62 mm
Length: ~ 115 mm

has 2 side buttons however, so that can be a pro or con
not a fan of the cable as well (braided g303 type I think), but that can be replaced easily

here is a review by a tester