Cisco just released a little brother to the Nexus 5020, the 5010. The 5010 provides the same features as the 5020, but in a 20 port x 10 gig 1ru form factor with one expansion slot.
The coolest thing about this chassis is its price. You can get 20 ports of line rate lossless fabric 10 Gig cheap (about 850 a port list price). At that price point, putting one of these top of rack starts to look very enticing to many people.