Zynga just released a new Mystery Bag Collection today. Seems to be a very difficult collection at first glance as 200 opened bags yielded just 1 piece. The vault bonus is very nice as it gives you 20 skill points to do with what you please. There is no revault option, so anything you get after vaulting will be trade bait or gifts for your lucky mafia. For those who are wondering, I added 3 of them to my wishlist before I opened all the bags and didn't get a single wishlist item. I usually get 6-10 "You've received an item from your Wishlist" mystery bags per day. Also, a few Mafia Wars players I talked to have said that they received a piece in a mystery bag and it did not show up in their inventory. No word yet if this is a glitch in the display or the inventory system. Good luck everybody!!
Update 4/20/11: Talk to a Zynga rep and got this quote: "Just clarification, when you already found one that day in a mystery bag - any other means that you found a superhero collection item will be gone." So, after I picked one up from a mystery bag, the 2nd one I received from my 5 day Daily Take bonus made my first disappear. Terrible terrible terrible practice by Zynga if you ask me. A different rep confirmed that these will not drop as Wishlist Items and only 1 will drop per day. So, if you received one on your Daily Take bonus, save your mystery bags for the following day or you will get Zynga'd. Good luck on this one as it appears it will take a while even if you do play your cards right.