I think it'll be a massive undertaking. Not certain. I guess it depends on the person! It doesn't need to be as detailed or pretty as these, but if anyone can make something of this caliber, or somewhat close to it, that'd be incredible.
I could do mountains and rivers and forests but I have no idea how I would draw cities... Hmm. Otherwise I think I might be able to do one of the antique style maps. They're quite illustrative, I think. I've drawn some landscape pieces in a similar style to some of those maps, look: [link] I'd be working on a tablet though, not traditional media like these... Could you sketch out sort of what you want, like where things would be and the names of places and make it available to anyone who wanted to do this map? That way I think more people could be interested. I'll see what I can do, but if I think it'll be too much work I can try and spread the word that you want help if you like.
I've never made a map before but I could have a go if you like? What sort of thing did you have in mind? If it's going to be a massive undertaking I probably won't be able to though, as I go back to college on Monday.