How about the Adobe Flex SDK? It's free (if you opt to not purchase the Flex Builder Integrated Development Environment) and it has a command line compiler that creates .swf files. Would there be any incompatibilities with Armor Games if I submit an .swf file created from Flex?
Yes it would (I believe... 99% certain someone point it out if I'm wrong), although there isn't the handy integrated graphics designer, so making a game would just be a harder task in general. You can still give it a try though.
I am 100% positive you will not find said file converter, but you should still be encouraged to try. And to be honest, I don't think there is anything "simple" with which you can make games. Well, good luck!