There are other companies out there that make such military model sets out of bricks.
One is Brickmania, which advertises that they use authentic LEGO parts. LEGO for its part, and with memories of WWII, has sworn never to make military based models. My personal opinion is that Brickmania is no more authentic in its models than COBI, does not seem to have a consistent inventory available, and is about twice the cost per kit.
If you shop on eBay and Amazon, you will find other companies that make such kits from all over the world. If find a kit you like, make sure to see if there are multiple listings for the same thing. Sometimes there can be quite a bit of difference in the price, depending on the vendor.
On eBay and Amazon, you can find occasional listings for Oxford Block, which despite its Anglo name is from South Korea. They have a really neat looking WWII era "Dragon Wagon" tank recovery and transport vehicle.
On eBay and Amazon, you can also find SLUBAN, which I believe is from China. While less expensive, the level of realism also looks to be diminished:
Xingbao is also from China:
There are also some very odd listings on eBay from an unnamed company from China: