I only got three with my level 50 assassin, 4 with my level 50 mechro, and i have already found 4 with my level 28 maya. This does not include the firehawk shield or grinding boss fight for drops, just random oranges from chests and enemies.
I think that's the orange he was talking about...and don't feel bad, I took my commando to lvl 50 without getting an orange. You can tip moxxi about 10 to 20 g's for a decent gun...then another 10 to 20 for her other gun. However I'm pretty sure you can only do it once per play through so I don't know if you want to. They are purples tho I believe.
you can do it repeatedly. Though the weapons scale to your level so its best to do it only once in a while. Also Moxxxi sometimes glitches and won't give a second gun if you try to get both guns at the same time.
Pretty much your only realistic shot at legendaries on your run from lvl 1-50 are when you face bosses that have specific legendary drops. That's why it isn't out of the ordinary to get things like a level 1 Hornet, level 4 bonus package, level 30 Warrior drops, etc.