A wall plate exists for just about everything that is worth doing.
I haven't seen a wall plate for a parallel port, probably because (not being cynical) it's not worth doing.
Parallel, aka IEEE1284, is good for maybe 50' for slow speed stuff, and high speed stuff like modern printers, maybe 25'.
The better solution is to run ethernet over CAT5 to the study from the basement, and use a little print server box such as this:
[Link: linksys.com]or you can forget about the wires and use this one:
[Link: linksys.com]Then any computer on the network can use the printer, and chances are, it will be alot more reliable than running a parallel cable in the walls.
-Bill