Nintendo’s new commercial finally shows off the new L and R buttons, as well as the stylus’s home. Screen captures included.
Two days ago Nintendo of Japan launched its promotional Nintendo DS website with the first Nintendo DS commercial. Today, Nintendo posted a second commercial which provides our first good look at the back of the redesigned Nintendo DS

Although we already know that Nintendo ditched its ugly red E3 trigger buttons, the commercial demonstrates just how comfortable the buttons are. They appear to be a compromise between the original GBA’s broader paddle and the SP’s stubbier but uniform design.

The commercial also gives us a glimpse at the stylus’s holding place: a hole near the R button. The pen is inserted perpendicularly to the system.
The bottom of the Nintendo DS also appears to curve outward at the system's edges, which should make the DS more ergonomic.