All power to you - assuming that you are serious about this, and not just a passing thought. @BjornAgain gives some very good advice - speak to other bar owners, and also other (non-bar) farang business owners, do you research, perhaps speak with a lawyer and be very well-prepared, especially if you have not owned a business before. By all means, it is possible as there are numerous successful farang-owned businesses throughout Thailand but I'm sure there would be more red tape to cross compared to a Thai national, and it won't be a walk in the park. If it eventuates, I will happily patronise your bar.