Bitcoin gambling is something that the online gaming industry has, so far, been very slow to adopt. There's some talk of Bitcoin, but the implementation is slow. This is simply down to awareness and market penetration in the first instance. There is also going to be some degree of caution from those operators in licensed jurisdictions, since they will not want to rock the boat by bringing in a form of currency that the local regulators do not understand. It's all down to taxes at the end of the day. You might find that regulated operators are going to be less likely to run off with your BTC if there is a legitimate operation behind the website.
Anyhow, back the the important question, There are some regulated operators who are implementing Bitcoin into their platforms. Ask your favourites to implement Bitcoin as a deposit method and see what they come back with. This industry does listen to players. Talk to them. The more people who do, the faster we will see movement.
For sportbetting, I will plug these guys:
https://www.cloudbet.com/No, I do not work with them, I just got chatting to one of their people in a bar and liked what they're doing.