An oversize version of the 90dg-Joining Plate that fit 40x40 V-slot profile.
40x40 90dg-Joining Plate
Please feel free to make, hack and use as you please.
Finished products can be found here: https://makersupplies.dk
More info in this video:

40x40 90dg-Joining Plate 2019-08-23
An oversize version of the 90dg-Joining Plate that fit 40x40 V-slot profile