Hadn't done these for a while and now I remember why! If you want to work your grip strength like no other I'd suggest giving bar hangs a try. Here's how: Hang from a chinup bar with a wide grip and then...hang. Try to hang for 45 seconds with out moving at a full dead hang. Rest a minute or so and try to do about 3 sets. Not only will your forearms and hands be on fire, you'll also be working your back isometrically. Now that these are in my training for the next 4 weeks, I'm gonna try to go 5 seconds longer each set each week. I'd think if you did this and then a lighter than normal set of farmer walks, your grip strength would be helped greatly!
Danny: Blah, I've tried those before and it's unbelievably brutal. I use two handed more often, it's fun (and torture) to keep working to break your record.