I'm currently happy with is my converted to non restricted Bushmaster ACR.
I'm a Swiss guy myself, but you would likely have to buy used, and they certainly are not compact. With that in mind, I would agree with cr5. I haven't owned an ACR, but have handled them, and they are brilliant. ACR would be an awesome non restricted gun to own.
As a side note, I'm a lefty as well, and have found all of the guns I will mention to be just fine to shoot as a lefty, and would not change much about them. The Tavor I have a even run with the right bolt in for 3 gun. Not an issue. I know you want a lefty gun, but honestly, all guns are pretty easily used by us southpaws.
I've owned an HK Sl8, which was alright. It had a pistol grip lower which made it nice to handle. Very precise with its bull barrel. Needed proprietary mags which sucks, but there is a lower to change that. A very fun gun, but a bit heavy. Can be had for XCR money or less for the stock configuration.
XCR is fun, and likely one of the least expensive options. I've owned two and been happy with them. One was insanely accurate, the other really not at all. Left side charging handle is kind of sad panda for me. I like right side so I can keep my strong hand on the gun.
My Swiss' have been my favourite rifles ever. They are just awesome, though a bit long. I recently sold my Tavor to get into a Swiss. Very accurate, very reliable, which made for some fun 3 gunning and is a deadly coyote hunter. There is some poi shift with the bipod. I recently did a thread highlighting that. Uses proprietary mags, however they look cool and are strong as anything else. You do mag changes like an Ak, which is either fun and awesome, or crappy, depending on your view. I prefer the rocking mags over AR style.
Tavor is a gorgeous rifle, which you are aware of. It shoots reasonably accurately, but always reliably. I had some issues with some mags not feeding all the time, and shooting from prone was sometimes an issue. I killed a lot of coyotes with this gun.
I own an AR, but don't know much about them. I just own one to be an AR owner

they are very light, and a lot of fun to manipulate. But I can't take it in the tractor, so I don't use it much.
Long story short, my recommendation would be:
ACR non restricted
Tavor
SL8
If you can get over buying used and the length issue, get a a Swiss! Or find a non restricted Swiss carbine, apparently they are just the cats meow.