If you happen to allow non-WotC products, there's a nice book called Beyond Monks: The Art of the Fight or something like that made by the Chainmail Bikini company. It's all about monks (including prestige classes, feats, and so on that all use Monk abilities to power, as well as a more martially-oriented monk base class called the Martial Artist). There's a feat (oddly named Leap of the Clouds...) that basically changes how you calculate jumps. In short, a standing high jump's DC now equals your Jump Check result. When making a long jump, you multiply your check by 4 to determine how far you jump. When you have a running start, you double your result as well (for a x2 to your check for a running high jump, or x8 to your check for a running long jump).
So, if you want to jump 20 feet straight up, without a running start, you have to get a 20 on your jump check. With a running start, that's a 10. If you're making a long jump, an 80 foot standing jump is a DC 20, and with a running start it's a DC 10.
There's then another feat (requiring this as a prerequisite) that allows you to Fly a certain number of rounds per day. I'll try to find this book in my collection soon for the specifics. In case you're thinking it's too powerful, the prereqs require you to be around 10th level or so to take the first one- so by that point, Fly spells and potions are commonplace, so who cares if you can jump 100 feet straight up? So can the mage, 5 levels earlier.