For those that may not know, the Third Wire Strike Fighters series sims are highly moddable and have had tons of free WW2 addons for years.
Finally, some very good P-61s are available.
Because this sim was designed for 1960's jets, radar is supported, though the exact display of the early WW2 radars is not supported.
To the best of my knowledge, this is the first time you can decently model night fighters like the P-61 in a PC sim.
With the appropriate downloaded mods, it would be very easy to recreate many if not all of the night fighter versus night bomber situations in WW2.
You can get more information at combatace.com , which is a fansite that hosts a lot of the free user mods.