http://www.fiercewireless.com/ctialive/story/sprint-counts-600000-femtocells-plans-update-airave/2012-05-09
The article linked above mentions new Airave's that support EVDO on 800, but for some reason they left out whether it will support LTE or not. So now we know that Sprint wants to upgrade the Airave, but they won't detail data capabilities.