As far as I know bustadice pays the highest maximum reward on a single bet followed by primedice and Betcoin and lot others but its literally impossible to high the maximum outcome unless you are enough luck to win the lottery. 
How much is the max profit per bet on bustadice? I do not know about it so let me know if you know about.
Anyway here is a list : https://bitcoinplay.net/bitcoin-dice/ Which contains all the information along with maximum reward as well but don't trust the list completely just use it as reference and cross check the information on the official websites before going for it.
The list on that site is not updated obviously and should not be trusted at all because there is still Safedice and Megadice on the list. Two sites that has bad reputation. Safedice is indeed was a trusted site but there is a big problem for many months due to the inactivity of the owner for too long time while at the same time there are many players experience withdrawal issues.