I would like to propose the geoElevation tag for recording the geographic elevation of a specific site. To me this seems like a very natural extension of the existing geo tags, especially geoCoord, but I'm interested in hearing others' thoughts.

This seems straight forward, I am going to add it to the working 551 documents as follows:

// Elevation above sea-level of the location 
def geoElevation : Number<length>