To my knowledge no one has done a No.4(T) bracket with a Picatinny rail built in. Using NATO STANAG rings, such as EAW used to make, with an IWS bracket was one option some people pursued.

Nor has anyone done a standard bracket with 30mm rings rather than the standard 1". The issue would be ensuring adequate clearance for the scope diameters, particularly the objective lens housings which can vary widely of course.