We watched a show on Grand Canyon rafting tours, and I didn't realize it was such a long trip... some of them were taking a couple weeks! Is that what you had in mind? Looked great, but caution, reservations are made YEARS in advance.
I checked out the Hatch site, and their 7-day trip costs $1850. They also have a 4-day trip for $925, but you have to either hike in or out at the midpoint.
Rafting the whole canyon takes the two weeks. But you can do part in a week.
Unless I get vey series about South Beach (or something), I'm pretty sure I couldn't physically do the hike.
The advance reservation is why I'm thinking my 50th birthday. That's still three years (and two days) away...