Seriously, Willy? You can't walk up a sledding hill? I'm not completely sure how I feel about skiers using lifts. If you're that worried about overexerting yourself, maybe you should just stay at home and get a sledding game for the Wii. To answer your question, though: 1) Yes, there are resorts with great tubing hills, but none are worth visiting exclusively for that purpose. Some notable ones are listed below. 2) The best sledding hills are generally off the beaten path and require you to, ugh, climb back up—and I've got a link to a database that includes some of them. And 3) you're right, there is a really long sledding course in Switzerland (it stretches 3/4 of a mile, not five miles) called the Cresta Run.
Now, regarding the resort-based tubing hills. A whole bunch of ski areas across the country have incorporated them as an added draw to get families to the mountain beyond simply skiing and snowboarding. Keystone and Vail in Colorado, and California's Heavenly, operate runs in the afternoons that people of all ages can sled or tube. I used to go tubing with my kids at Smuggler's Notch in Vermont at the end of a day on the slopes—though our favorite place to lug our old Flexible Flyer was on a hill above the Nordic trails at the Catamount Outdoor Family Center near Burlington. Now that we're in the mountains of North Carolina, we generally just head to the local golf course, but there's a popular tubing run at nearby Beech Mountain and another quite a bit north at Massanutten in Virginia.
For potential help in finding local sledding hills--if you're not afraid to huff back up them--try sledriding.com . Started by a sledding buff in Missouri named Steven King, it includes a nationwide database on great, hidden spots.
Finally, for that epic hill you mentioned in Switzerland. It's called the Cresta Run, a 1,200-yard natural-ice sledding track first created in the 1880s near the town of St. Moritz. It drops 500 feet in elevation (hurtling riders downward as fast as 80 miles per hour) and was used as the skeleton run in two Olympic Games. To ride it, you have to become a supplementary member of the St. Moritz Toboganning Club. Your first five rides cost about $600, as a package deal, and then each ride after that costs $50. I must note that women aren't allowed on the Cresta Run, which means that I have to give it my official stamp of disapproval.