USIA have a couple of boot options, and one is a VERY heavy boot designed for shore diving. My instructor has those on his USIA suit (we're a dealer). However, a couple of months back, someone was asking a simila question on here and a poster sent a link to a waterproof boot that our military guys use. The boots were available to the public and the boot looked PERFECT for this application. I can't remember the name of the boot, but the thread was asking about diving in areas with broken glass, so that might work in a search...
If you find it, re-post that link. I want to save it.