I have a Bushy shorty 14.5 with the AK brake and I just love it !!!! some have commented about the weight of the hbar, not a problem as far as I am concerned.
As far as the AK brake is concerned, I bought it with it because I liked the way it looked and it was all that was available at the time.some say its too loud, again no problem for me.(and no complaints or foul looks at the range either).
just my .02
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In reference to number 1, I believe 11.5 and 14.5 are NFA  (Class 3) unless you permanently attach a muzzle device.

In reference to number 2, can you say ARMALITE?  Product and customer service beat all others.  Their midlength carbine handguards are great.  You might also consider this, especially since you mentioned something light:
[img]http://www.armalite.com/sales/catalog/rifles/ar180/wholeRifle_small.jpg[/img]

Price is right, too.  MSRP of $590, which means probably less at the dealer.  A lot of people knock it's looks but yet they love the A3 or A4 (depending on manufacturer) flattops and this is basically a flattop.  You have the flattop capability without having to remove the front sight and  it has an integral dovetail scope mount on which the original 180 mounts will work.  I am sure ArmaLite is going to be producing the scope mounts and B-Square already makes them for the original, which, as I said, will work on the new 180B.

Bushmaster Shorty "AK", 14.5" barrel

Knock Knock.....its still ugly.

[spank]  Don't buy one then.