Tokyo Marui previously built sought after RC models before it fully devoted itself to building airsoft guns and one of the last RC models is the JGSDF Type 90 RC Airsoft Tank that was made with the official approval of the JSDF. It uses 8 8X AA batteries for to power it and 1X 006P (9V) battery for the transmitter. It shoots 6mm BBs and you can load up to 40BBs. Should be nice for some airsoft tank battles. You can still find some on eBay if you are looking for  one and Mach Sakai got his hands on one for a review.