Until UVHM, you can totally go full Brawn, That’s what I would do if I was running an allegiance build other than Maliwan. Running all Maliwan gives you the option to either do that, of rely on off-hand Moxxi weapons for survival.
If you go full Brawn, I would go like this: http://bl2skills.com/gunzerker.html#000000000000000000000055005104051
Then spend the other points into Rampage.
If you plan on off-handing a Moxxie weapon, I would go like this instead: http://bl2skills.com/gunzerker.html#550001501005055010515100000000000
Using a Moxxi gun gives you more options and makes you better at both dealing and taking damage, but it restricts your gun choice a bit.
Forget about the Chère Amie, it’s not as good as the other options for Moxxi guns. The Rubi, Grog, Bad/Good touche are all better.
For your loadout, assuming you use a rubi in your off-hand, or something similar, I think a great mix would be a Snider Sniper rifle (or a Pimpernel if you bother to farmfor one) and a Berserker or War Dog COM. (If you use the War Dog, use this spec instead: http://bl2skills.com/gunzerker.html#550001401005105015515100000000000 )
Otherwise, like I said, Dual Rubi is also a nice setup
Spec: http://bl2skills.com/gunzerker.html#505001501005045010515101000000000
Combined with a Monk (Chaotic evil, Money shot) or Renegade COM (Blue, suave prefix, Incite as a second skill)
SMGs can also work, but not as well as the previous 2 suggestions IMO, though you get to pick any slag SMG in your off-hand as your Moxxi weapon will be in your main hand, so points for versatility.
If you plan on going with Brawn, I suggest you find a good Titan or Beast COM to supplement your tanking abilities.
For your shield, it’s a no-brainer: the FOTF has Sal’s name written on it (well, it also has Krieg’s in bigger, but Sal is there as well)
If you’re using a Brawn build however, an Adaptive shield would be a wiser choice, especially since the novas will not heal you as when you have a Moxxi gun.
Relic is Sheriff’s badge if using pistols, then Vitality if using Brawn, then Either a BOTA or Maliwan Allegiance relic.
As for Brawn in UVHM… forget it
Some VERY skillful players have managed it at level 72 (yes, it’s easier at 72 than at 50 in UVHM) but it’s not something I would recommend.
Sal’s survivability in UVHM goes through Moxxi weapons.
the only skills worth specing into in the Brawn tree for the average build are Hard to Kill and Incite… past that you will have to waste a lot of points to get to anything else that’s worth it, and those points are usually better spent elsewhere.
(On another note, the Brawn tree is just ONE redesigned skill away from being perfectly viable in UVHM… not gonna happen though)