If it is the quickest path to money COBOL or any mainframe development is still top dog. There is virtually no competition in this space from new developers and has a seriously aging population. While the # of jobs in sheer volume is lower the jobs to head count is much higher. Just applying to a COBOL job with no experience but a "I'm willing to learn" will land you the job many times, if you have previous unrelated development experience. COBOL programmers are commanding $40 hr in India which is close to on par with a mid-level Java developer in the states. That said it's not sexy work.