Here's an alteration I've done successfully a couple of times for jeans where the front rise is too low for me. After the alteration you won't be able to wear anything tucked in, but I never do so it's not a problem for me.
To get about an inch extra rise, I use 1.5 inch wide grosgrain ribbon (it's the ribbon that has ridges on it) that you can buy at any fabric store, at the top edge of the jeans waistband. You will need twice the measurement of the front band from seam to seam plus another couple of inches for turning under to make it look neat. Cut the length in half and then fold each piece in half (so now you have a piece for each side of the jeans waist). Place the folded edge of one piece even with the front edge of the waistband with the long ribbon edges meeting and placed on the inside of the waistband. Pin the ribbon along the waistband edge all the way to the side seam making the edges of the ribbon meet (so you have a double thickness, this gives the waistband the extra body it needs). I taper it so when it meets the side seam it's even with the top of the original waistband (the extra ribbon ends up on the inside of the jeans). When you get to the side seam turn both of the raw edges of the ribbon to the inside (between the two pieces of ribbon, so it won't ravel when washed). Now sew along all 4 edges of the ribbon to both attach to the waistband and to keep both thicknesses of the ribbon together. When I get to a belt loop I stop the sewing and then start again just after the loop (so the belt loops can still be used). You can stitch right over them if you never want to use them though. Now do the other side the same way. When I wear the jeans I just use a safety pin to keep the front edges of the ribbon together (they're overlapped just like the original waistband is), it makes for no extra bumps like a button would.
I hope the directions are clear, but if there are any questions i'll be happy to answer them. It sounds more complicated than it really is, if you have basic sewing skills you can certainly do this and save a pair of jeans that otherwise would not be comfortable.