The waterproof boots I own are La Canadienne (and my foot is not narrow and I take the *smaller* of my two sizes in their boots -- go figure!); Aquatalia (typically quite narrow, I always take the larger of my two sizes); and Blondo -- which are generally medium width but can run on the short side so sometimes don't work for those with longer toes. (In a round toed style I kept bumping my very short toes.)
Having said that, as Sharan says, Blondo is economical and can work very well when they work, so worth a try!
I think Naturalizer may make some wider width waterproof boots -- worth checking it out!
I also have Blundstones but their fit is very different and I, too, have trouble getting them to work for me, though I continue to try and buy because they are great for garden, light hiking trails, mucking about. My current Blundstones are lined with two insoles for a better fit. I only wear them very casually.
