A friend of mine started playing around with Hercules and got a job with an IBM partner company. He just took a new job now at 2.5x the money I'm making, and I make good money :)

The companies who do mainframe gigs know the market is small and they would probably accept new talent that has no real world experience. All that's required is some experience (emulator counts), and a job history that says you're not an idiot and can get the job (any job) done. My friend was just a regular linux sysadmin before he got into mainframe gigs.