There are lots of options:

http://wiki.openstreetmap.org/wiki/OSM_on_Paper

I haven't used any of them so I don't have anything resembling a recommendation. You could try asking on https://lists.openstreetmap.org/listinfo/talk-gb , the community there is pretty active so someone might have a suggestion for a nicely done map.

I make a lot of maps in my spare time and have access to a large scale printer. Give me a ping in the next few days and I'll see what I can do for you.