I recently found out about a product that looks like it might be useful for those of us who shoot DSLRs underground. It's called Camera Armor, and is a silicone casing that covers much of the camera controls, the screen, and part of the lens barrel. It's not a full enclosure, so not waterproofing. It would primarily protect against impacts and possibly help keep dust or grit out of the controls. Here's the web site for it:http://made-products.com/
It runs about $45 on ebay. I haven't had a hands-on look at it yet, and I'm wondering if anyone here has used it. My one concern is whether it makes the controls any more difficult to use.