I'm 5'6" too and I just went through the same process of trying to decide if a 29er El Rey would be the right choice or to go with a Salty. So, I rode my buddy's 29er and after much consideration I went with a Salty. The 29er felt great, handled great, climbed great, but felt really big and awkward to me on technical steep descents.
So I came up with a better solution... get an El Saltamontes for my XC / All Mountain Bike and then buy an El Padrino 29er, set it up purely for XC with a 9 speed 11/32 cassette in the rear and one 44 tooth chain ring in the front. Drop the front shifter and front deraileur to shave some weight. That's my solution... the best of both. Running a 29er on XC trails will allow me to ride a 29er without getting into any hairy descents for my short stance. And I'll ride my Salty all other times.
That's why I'm selling my Pantera, so I can get a Padrino... now that I got my Salty built up and ready to roll.
Scots