Hey Saltedleech - before you buy, check out The Boundary Waters Journal Trading Post. I've had his map case for 6 years. I believe it is a  beafed up version of the GG one. It works perfect for me. It is not real big, about the size you are looking for.  You can only view 1 side but it keeps water out well and it is tough. I had the plastic clasp (like the clasp on most packs )snapped around my thwart and It was strong enough to hold my eagle fish finder on when a floppy northern got caught in the transducer cable :o. I spray the cordura back side each year w/ a heavy coat of camp dry. I think it is around $25. Good luck!