There all kinds of jeans styles out there. Some styles would lend themselves to altering the waist but regular Levi style jeans with the watch pockets and yokes would be a little daunting. I suppose you could separate the yoke portion from the rest and and either face the waist or put in a waist band. You would have to move the zipper down and you would lose the watch pocket. The front pockets would be higher as well as the back pockets unless you chose to take them out and move them down too. This is if the width of the yoke is enough to lower the waist where you want it. Then again, I looked at a pair I have and I know that different designers have varying yoke widths. Also, the yoke doesn't go across the front, only the back so you would have to lower the front by hand without a seam to guide you.

Personally, I know that cool weather is coming so I would be more inclined to go back to Goodwill and look for some shorts to wear this summer. (sitting here in S. Texas in 100+ weather.)