Here's a glimpse of one of the new mesh butts out now, the Perfect BUM by G. Inc. Any phat azz skin or clothes applier can be adapted to it by dropping in the note card of your skin or clothes applier (I am very challenged in these areas and I did it, so ya know it's easy peasy, instructions included). Plus, many clothing designers are including the Perfect BUM appliers now (there's a list of which ones at the store).
It costs 750L and includes a rigged mesh and a fitted mesh version, for the new updated viewers. It also comes with a layers HUD, and default skin, pants and underpants appliers, and the alphas.
I took pictures using the rigged mesh butt and also, the fitted mesh butt (yes, I went there...I downloaded the SL viewer, and you can tell by the graphics quality haha).
The rigged mesh version is a tight, cute butt, seen in the first two photos below.
And below, the fitted mesh with my sliders maxed out (my shape couldn't slide anymore but the fitted mesh went everywhere the sliders went).
Free Developers Packs on the wall.