Any Java or PHP is a plus, but RPG is key.  
Work from home.

Are people still running as/400, or is it just running on something that is emulating it?

I'm continuously amazed at the amount of legacy stuff that is out there. My BIL still runs his business on a Norstar Key System that was used when I initially installed it in the mid-90s. I've installed it in 4 or 5 offices over the years. I just re-installed it 2-3 months ago. There was a news article recently about the Voyager spacecraft still (mostly) working after 40 years.

Sorry for the slight hijack, I don't know anybody that does RPG, but I suspect there are a lot of old-timers who would love to get a paycheck working from home.

I have machines at work that run on programming and controllers from the 80's. Some of my stuff would require scouring ebay for replacement electronics since they have been obsolete for over 15 years. I can believe it.