There is no such thing as low rise motorcycle pants since they need to provide hip coverage. Another option would be to look at a custom fitted one piece suite. Some such as Teiz are priced fairly reasonably. They are also easy to get on and off.
Olympia pants, at least some models are sold by the waste size, rather than the usual, small, med, larg for more accurate sizing. The also have stretch panels at the hips to allow a more variable fit depending on whether you have a belly or not.