Cat Form Stealth Bar
 

When druids shift into cat form the bars should switch to have all the stealth attacks. Like the rogue

Actually, not for a long while now. Unless you used to use a Bar addon like Bartender.

The stealth bar for the druid just highlights the abilities you are able to use and doesn't give you an extra bar to use.

If you run WoW without any addons you will see the same effect happen.

I believe however that Scott is planning on making the action bars more flexible in nUI6 but whether it includes using one of the bars as a druid stealth bar I don't know.

Xrystal is correct, there is no druid stealth bar in the Blizzard use interface, and thus none in nUI5 either. In due time nUI6 will support the druid stealth bar though.