Currently, the house edge is capped at 3%, and we'll lift it to unlimited very soon, that means you can take away the whole bankroll with a single bet under a high house edge, stay tuned guys!
I don't think so:
You can win 0.5% of the bank with a 1% edge,
Win 1% of the bank with a 2% edge, etc.
So to win 100% of the bank, the house edge would need to be 200%.
percentage_chance_to_win = (100 - house_edge_percent) / payout_multiplier
If the house edge goes bigger than 100%, the player's chance to win goes negative...
So the most you can let a player win in a single bet is 49.99% of the bankroll.
At that point, supposing they want to double their money, their chance to do so is (100 - 99.98) / 2 = 0.02/2 = 0.01%.
So that's a one-in-ten-thousand chance of doubling their money.
In other words, there's a point at which it becomes silly, and the player would be better off just using a site with a bigger bankroll...