If by "green screen" you mean 3270 terminal, then ... yes, but it would be pretty hard. The networking hardware for a 3270 is pretty expensive. (I was going to say "getting pretty expensive," but in reality SNA has always been expensive; it's just that other networking hardware has gotten dirt cheap by comparison.) And, of course, you need some sort of actual backend computer to attach the terminal to.

But sure, if you had a terminal, a spare IBM system (the iSeries is probably the lowest end) set up to support SNA, and then a networking controller to attach the 3270 to, you could probably get Lynx working.

Alternately, if you just want the effect, you could just pick up an old green/black monochrome display and hook it up (via a physical adapter) to any VGA card. Buggy implementations excepted, all VGA cards should be backwards-compatible to MGA.

Add a nice IBM Model M keyboard and you'd be all set. I suspect someone has probably done this as a case mod before (if not ... I might); stick a modern mobo in an old IBM PC case with the original monitor and keyboard.

Yes. Find any of a number of old-school serial terminals, attach to the serial port on a PC running linux, voila!

http://vt100.net/