All good comments - a few things to consider:
- I can do a more traditional bike, or even something like the law giver no problem - this bike was more geared towards combat, with the large solid rubber wheels, armored canopy, etc. Sailing into combat on a motorcycle would be insane - but as always, the rule of cool will prevail.
- There's a BIG problem when it comes to bikes - and that's casting. Take a look at a 6mm bike and you'll notice what I'm talking about. There's a lot of details and negative space simply "filled in". For example - any space between the arms - that's going to have to be solid - it's important that the design of the bike goes a long way to hide this fact, or it will be quite the eyesore.
- I can do something a bit more futuristic like Akira, but steps in that direction have so far been met with resistance. "Low Tech" / "Grim Dark" seem to be the order of the day. I'll mock something up and see...
- This isn't a complete model - so details like exhausts and such have not been added yet.
- Blip - You nailed the main source of inspiration here

The big guard in the back is something the one in the movie sorely needs! All I can think every time I see Batman riding that thing is his cape getting caught in the back wheel and pulling him off! lol
Anyways, I'll get plugging away.