I've been pondering starting a consulting business to help small companies maintain or migrate old apps written in stuff that's not supported any more, because I suspect this might be a good business opportunity ("where there's muck, there's brass"), with not too much competition, since people tend to prefer focusing on new technologies. I personally have no issue with using old languages, tools and platforms.

Is anyone doing something similar? My main fear would be failure to deliver, since there is more uncertainty in the process; you have to make sure you have the source code from the client, and that you can find not just the development tools (eBay, etc.) but also the manuals and the OS to run them, and so on.