P-90 is a cool SMG, and there's even a semi-automatic civies version. The newer assault version is the FN F-2000, and there's even a grenade launcher on it.
But I'd prefer the P-90. It's an interesting gun, and I think I've seen some SW concept art with the P-90 as reference. In fact, here's the "image attack" for a background prop used for ep2. I haven't seen ep2 in a long time, and it's packed away somewhere from when we were trying to move, but didn't , and we haven't unpacked everything yet.