I would argue that if you are already a serious professional quality trumpeter you have ALREADY making a life out of playing trumpet! Just keep it up!
As to making a LIVING playing trumpet EXCLUSIVELY, hang tough. The going is VERY tough! It can be done, though.
One thought about teaching privately: if you have 30 or 40 students (or more, as many of my friends do), you ARE a teacher! However, that is a beautiful thing!
for more info...
http://www.brass-forum.co.uk/Article...heTrenches.htm
When it comes to classical/legit work, listen to Manny and company! The know far more about that than I ever will.
Peace.
Nick