Burms are pythons so you still have the fast metabolism, food bill, and messes of a giant python. They're just less likely as adults to draw your blood, though babies can be defensive and nippy.
Dumerils boas are another good option. They are fairly big, thick-bodied ground snakes, but they're extremely laid back. Like the boa imperator they eat monthly as adults, so there's less daily clean-up involved.