I have a Vector 53, in .223, and am pleased with it, will be better when I am more sighted in, but that's another story. Point is vector is coming out with MP 5 clones, pretty well done (in my opinion), in 9mm, .40, 10mm and maybe even .357 Sig.
You might consider checking them out as an alternative.
Starting out with Short Barreled Rifle is not a bad thing, I don't think.
HTH