Here’s an idea for lend-lease: add a new unit type called “Supply Crate.”
Crates cost 5 IPCs each, can be built at any factory, can be loaded onto and unloaded from any transport as if they were an infantry unit (so a transport could carry 2 crates, or a crate and a tank, or a crate and an infantry, or any similar combination), and do not participate in combat. They move 1 territory per turn, but only during the non-combat move.
At the start of your turn, if there is a supply crate in a territory with a factory that you control, then you may convert it into 5 IPCs for your treasury. Each factory can only convert 1 crate per turn per IPC value of the territory. For example, if the British build 4 Supply Crates in London on UK1 and ship them to Archangel on UK2 using 2 transports, then those Supply Crates could be unloaded in Archangel on UK2 and then, on UK3, walk to Leningrad. On R4, Russia would see that it had supply crates in one of its territories with a factory, and convert 2 supply crates into 10 IPCs. Then, on R5, Russia could covert the remaining 2 supply crates into another 10 IPCs, for a total of 20 IPCs of lend-lease.
Also, if after combat there is a supply crate in a territory that you have just conquered, then you must immediately “loot” them by converting them into 3 IPCs each for your treasury. The money will remain in your treasury until your next regular opportunity to purchase units. There is no limit on how many crates you can loot in a single turn.
The Supply Crate would help facilitate the creation of a Canadian power (by giving Canada something to do besides just build fighters and fly them to Moscow, and by giving them a reason to maintain a navy), would help fill the otherwise lackluster 5-IPC slot in the unit roster, and would more realistically simulate the war and sea and the ability of the Russians to field massive armies later in the war using the economic might of the Western Allies. Instead of a stack of 30 Russian infantry with 6 British fighters, you could have a stack of 30 Russian infantry, 10 Russian artillery, and 2 Russian tanks – but only if you can keep the sea lanes reasonably clear.
Supply Crates could also be used as a less disruptive form of bidding in conventional G40: because supply crates don’t unbalance any turn 1 battles, they’re a gentler way of giving the Allies some extra economic oomph.