Grootspoor.com offers several detailing sets for locomotives from PIKO and LGB. If I am not mistaken, Grootspoor originally did the design of those and later cooperated with Massoth for the distribution.
A new offering is a detailing set for the PIKO TEE diesel multiple unit train. This set of detailing parts contains all the parts you need for the decoration of both power car cabins. All parts are plastic, and come in white. Looking at the pictures, it seems the parts are 3D printed.
The detailing sets is available for € 259,95. Link: Grootspoor.com