Okay you forced me to open up the old spreadsheet I keep of all my mods installed. I do have a mod for the winter JPZR IV. It is called:
NewPz4
I believe this mod is at www.combatmission.com as part of a pack with the other Panzer IVs.
Also try www.combat-missions.net and use the MOD LIST for future reference. I believe this is the only JPZR IV winter mod available.
On a final note, Oh Fernando, Scipio, JuJu, Family, and the other way more talented than me modders is there a possibility that this might be done?