Watches have straps. And if those straps were sized to tie around your waist, you can use them for a belt. So, somebody did just that and called it the Belt Watch.
Made by Bless, the accessory can hold your trousers up just as capably as any of the leather and canvas belts you've got in the closet. Doing those ordinary belts one better, it has a digital watch integrated along the length of the band, so you can use it to check the time if you want to. Of course, you'll have to bend down to do that, so better lose that tire in your gut or it's going to be a problem.
The Belt Watch is made from leather and measures 42 inches long. A digital Casio watch case is integrated a few inches from the buckle, hooked onto the strap similar to the way it would be on a regular wrist band. Sure, a timepiece wrapped around your waist makes little sense. You have to admit, though, it's a heck of an entertaining design. Heck, I'd wear one for the sheer novelty it.
Bless made the Belt Watch in black and natural leather colors, priced at $340. There's bad news, though. It's all sold out. The good news? You can probably DIY one, slicing up a belt and stitching an old Timex case onto it. And it probably won't even cost anywhere near $340.