Go have a look at Squadron's website. They have an excellent search tool. I found 32 results for 1:48 ordinance under Aircraft Accessories. Have you gone to all the local hobby stores? I don't remember off hand, but I may have a set of the Hasegawa WWII ordinance.
Grandfather flew A/B26's with the 13th bomb group in Korea, I'm working on accurizing one of his models. One thing he always talks about is how much ordnance theyd put on the wings, anything that would fit.
Bombs, rockets, napalm, flares you name it.
He had a model made by someone else and he's unhappy that it has nothing on the wings.
The man flew headlong into flak so thick you could walk on it through two wars. The least I could do is put some bombs on his plane.
OK, so we're talking USAF & 'wing mounted' ordinance for the Invader.
I know I've got a handful 500 lb. bombs & somewhere a few 'K' (1000 lb.). They also carried 'Tiny Tim' Rockets which you could make.
Write my Eddress & I'll hook you up. panotraguis@comcast.net