Just thought I would mention something, while it's not entirely related to the P.1000, Albeback52 has posted some of the up and coming Model Collect walker kits, and Sgt. Squarehead has mentioned the over emphasis on Luft/Wehr'46 and wunderwaffles, I just wanted to say that Model Collect is doing the walkers as part of their 1/72 Fist of Wars series figure as part of a gaming (tabletop maybe) set they are collaborating with a Japanese company for. Currently announced including, German Walkers, Soviet Walkers, a fake P.300 heavy tank and the P.1000 is considered to be informally part of this series. Based on other announcements, it's likely US and Japanese walkers/fictional '46 vehicles will be released in the future as well (regrettably nothing British related has been announced as of yet).
I know some of the guys at Model Collect, and their product (WWII amor mostly) appeal to a lot of the tabletop community which is why they've been looking to branch out, but their main focus will remain to be real life vehicles. I should also mention one of the Model Collect guys mentioned on a Chinese forum that the P.1000 started off as a semi joke, but as development on other models progressed (namely the E-100 series) and increased interest, they decided to proceed with making the actual thing.