A lens that might be useful is a Nikkor 450M f9-f128 in a Copal 3. It has an image circle of 440mm @f22, but goes way beyond that at higher numbered f stops. It weighs 1.41 pounds or 640 grams. That is at least several pounds less than the lens you originally requested.
Though no longer made this is a very popular lens and thus widely available used but in good condition on eBay or the forums. If your interests grow beyond 4x5 this lens will be useful on several other formats. I have carried mine from 4x5 to 8x10 and 7x17. The diagonal on 8x10 is 313mm. The diagonal on 7x17 is 464mm, confirming my statement that the coverage grows significantly at f stops above f22. I usually shoot the lens at f45-64 on the 7x17 and am very happy with the negatives.
Good luck in your hunt.
PS: If you are not already a member, you might want to join the Large Format Forum. http://www.largeformatphotography.info/forum/index.php. I have seen this lens offered there, but you need to be a member for 30 days before you can access the for sale section. "For Sale/Wanted" sub-forum, which is open only to those who have been members for 30 days or more.” The rules.