WedgeRock
Royal Flush
Would it be profitable for me to buy 2-3 hundred $1 to play like small stake limit hold 'em or something when they are mint/near mint, and take them out the door?
Profitable? Mint Paulsons (if you could buy them) cost more than $1 each. So yes. And you can always return them at face value and lose nothing.
Would i be able to sell them for significantly more than I "bought" them for?
Significantly? Depends on how desirable they are, but I would say they'd go for $200/rack as a ballpark, sight unseen.
Is this quite frowned upon by the casinos?
Well, they probably won't mind letting you take a few... Taking 2-3 racks will be frowned upon by some, but sometimes, you hit gin with the floor people and they don't mind helping you.
Make sure you tip. Make it easy on the next guy.