For me late war as allies is not really interesting but from others side i will like to play with many new toys you get in late 44-45 so i get idea for mod which will kill both problems at once.
This is obviously not historical mod but i'm trying to make it with what i have so stay with me next couple of lines..
Imagine that in some late 44(December) Soviets decide that confrontation with west is immanent so they decide to backup Japan to stay in war as long it can. At first secretly and as time pass more open..they main motive is to get more time to invent nukes or find way to deal with west, or whatever - not matter for this story they local goal is to make Japan alive as long as it can, but not to go into war with West as much as they can at same time..
So they make secret deal with Japan, they will not attack them on land (until conffontation become open Japan can use troops in Manchuria, beside border guards and skeleton forces ~2000AV on other fronts. Soviets will also give them oil & resources using rail lines between Vladivostok and Korea.
For Ironman it also can give them some equipment(nothing fancy some AAs and ARTs) and after confrontation with west become open (on example 1, jul) they can even send some troops not much but on example 2 armored division can make big difference..
So from tehnical point soviet will be disabled, no activation at all, plus some bases in Korea will get resource generation in amounts needed to give Japan player ability to continue Plane production in full and some fuel for ships who survived, Okinawa landing did stil not happend (for ironman ship list can be boosted a little).
Japan will need to ship those extra resource & fuel from Korea to Japan.
Scenario should start around 01 Mart 45' and play to 46', at scenario start time Japan should already have improved AA at key industry points and ART somwhere on map, it should also have new line of fighters entering date pushed to earlier dates (tehnology transfer + more resources aviable)
So bacis gameplay will be for Japan to prevent or halt any landing in force and protect sea lines to Korea, and allies can or attempt to break sea lines, or destroy industry or land in Korea or main islands..
Now i think this can be fairly interesant scenario if things given to Japan are balanced to give them enough defansive power and stil allow allied player to win if he play any good.
Now this is only idea and i have 0 expirence in making scenarious so if anyone will pick this idea up and make spomething from it it will be super to read some late war AARs from it, if not it is OK it is easy to have idea much harder to do something with it..