I have seen a few rigs with more than one awning, particularly big motorhomes. I don't see any reason why you couldn't add an awning.
Having said that, I personally don't care for all the maintenance involved with an awning, and the potential for damage and early failure. One is plenty for me.
They are a necessary evil, and if you can put up with the maintenance, go for it.
How about a stand-alone tent-type canopy?
Doug and Patience and Shelby the mutt
2015 Crossroads Sunset Trail Reserve ST26RB
2013 Ford F-150 3.5 EcoBoost XLT Supercab 4x4