according to scalemates and perth military modelling, Takom is going to extend it's range of Mk IV tanks by releasing a 1/35 Tadpole with 6" mortar, kit number TAK2015.
The promo banner for the kit states that it will have the glue-free workable tracks - I presume that's the easier click-together set not supplied with the normal Mk IV kits.
Takom's kits look excellent from what I've seen so far, so hopefully the tail angle will be correct, not too close to the horizontal.