I haven't come across just the pants in any stores yet. Honestly those would probably work fine for me, I'm just looking for something more waterproof when I'm kneeling. But figure I may as well get float bibs for peace of mind early and late ice.
It's not often I end up too cold. I work outdoors year round, I've got the baselayer combos nailed down for most situations. But there's no improvising waterproofing