Interesting discussion, which brings up a question. Define "venom".
Is a venomous snake any snake which can deliver hemotoxins and/or neurotoxins? If so, almost all snakes can fall into those categories. Or is it only when a certain amount of toxin is delivered? Is LD50 the only true measure of when something is or is not a venom? Or do you go by the physiological effects of a toxin?
I know that there's been enough work done with garter snakes to say that they are definitely mildly venomous. There is a hemotoxic quality to the Duvernoy's gland secretions which causes angioedema even in the absence of a true allergic reaction. It's fairly easy to tell the difference. If the bite area swells and bruises but there are not elevated levels of histamine, trypase and igE in the bloodstream it is a true toxin rather than an allergic reaction. There are documented cases both of true envenomation and also of allergic reactions caused by garter snake bites. Thus doctors of human medicine class garters as mildly venomous even though most herpetologists don't. I've never read whether that is also true of hogs or not.
Here's a little bibliography I found of colubrid envenomations and/or studies in case anyone is interested:
http://www.herper.com/snakearticles/rfvenbiblio.html