Yeah, the ramp comes in a three different heights: short, normal, and tall. I have short legs, so my girlfriend and I got the short model.
Both the ramp and wedge are available in multiple widths, as well. The normal width for both the ramp and wedge is 24", but there's a plus-sized 30" option for those who want a wider shape. And there now seems to be a 19" option for the wedge as well (but not the ramp), which would be good if you're planning to straddle it at any point.
I'm guessing EF carries the "normal" size, but hopefully they'll carry a full selection of Liberator products at some point in the future. Now that they're the same company, they really ought to do so.