How about a 120 mph Custom RV? You won't be complaining about being caught behind this rig! Words and Pictures by Jim Vogarino Sitting on the huge expanse of pure white salt, the evil looking all black motorhome looks even bigger than it is. Everything is black…windows, trim, head and tail light covers. It couldn't be more sinister.   Britt Palmer pulls himself out of the custom racing cockpit, ducking under a complex structure of roll cage. He’s a good sized guy, 6-2, maybe 6-3 and he gives a solid hand shake. You’d never know he is suffering from a debilitating disease that eventually will rob him of all movement. Right now he’s too excited.   "We’re headed home,” he says, slipping off his race togs and giving high fives to people who have gathered around the vehicle in his pit area during Speed Week 2013. “We came to just run for speed and I think we did pretty well." Bonneville Speed Week is pretty well known for odd vehicles and the 1977 GMC Kingsley motorhome easily fits that category if only because of its size. Sitting at the...