An interesting question having just obtained the Matador conversion. Do you wait for this to come along or press ahead. Remember Emhar has announced other Napoleonic sets over the years just like this and they have never been released. I hope I am wrong but i will not hold my breathe!
Another question is, if it does appear, will the angle of the tails be correct? As far as I can tell, the 1/35 model has the lower edge of the rear horns trailing along the ground, which would be incorrect - they should be angled upwards at the same angle as the shorter horns of a regular Mk IV, allowing the tank to rock back slightly with the shift of the centre of gravity. Hopefully a 1/72 version would get it right.
You could also get both the Mk IV tadpole (full kit!) as the Mk V from Modelltrans in 1/72 scale, and all versions of the Mk V from Early War Miniatures.