Not sure who makes the little guys, this one was given to me a few years ago in a box of models for a Christmas gift.
I wish I still had the package....maybe an online search will turn up something.
A quick search netted two results for a 1:35th scale MaK Fighting Suit that was offered by Hasegawa which included two models in the box. I had never seen these before and I did know of Hasegawa offering some of the MaK stuff previously though the fighting suits were not mentioned. Or I it could have been me not recognizing what I was looking at which is quite possible. :)
Click on thumbnails to go to
Comet Miniatures where you will have to scroll down to find the item.
Hasegawa P.K.A. Ausf M Melusine
Hasegawa P.K.A. Ausf G Gustav
Some of the other results seem to indicate that there are other sources for 35th scale MaK fighting suit kits but no real names are given so they may be limited run garage and basement operations. I always thought the MaK had ptotential but the scale was not compatible with other armor or aircraft subjects so I usually ignored it.