I'm starting to put together an Imperial Guard army for 40k, which can be quite expensive with the amount of armour you need to field. Enter the Ragnarok. The Ragnarok is a Leman Russ substitute fielded by the Death Korps of Krieg, loaded up with a battlecannon and a pair of heavy stubbers. Well, my version has the battlecannon, but the twin heavy stubbers are replaced with a heavy bolter - in other words, it's a direct Leman Russ substitute.
The basis of the Ragnarok is a 1/48 scale KV-2 produced by HobbyBoss. All that you need to do is to replace the gun with a plastic tube equivalent, replace the hull machine gun with a heavy bolter, and 40k-ify the top of the turret with a new hatch and smoke launchers. I'm sure most players have the majority of the necessary parts anyway.
As a comparison, the hull of the Ragnarok and the Leman Russ above are the same width (excluding sponsons), the same height to within 2mm, and the Ragnarok is about 20mm longer. And the best part is, I can get three Ragnaroks for the price of a single Leman Russ. I think I will have six of the Ragnaroks (I have three kits so far), armed as Battle Tanks and Demolishers, and a couple of Leman Russ as the more unusual variants - an Executioner, a Vanquisher, and an Exterminator ,the last of these to be painted in black as a commissar's vehicle - a full heavy bolter loadout should remind the troops not to retreat!
All I need to do is to work out how to add sponsons to the KV-2 kit...