I think
Cammie is a cute nickname.
I've never met or heard of a
Camille, so I don't conside3r it common at all.
Camilla Parker-Bowles is the only one I know of from real life.
I pronounce it kah-MEEL.
For some other names with
Cammie as a nickname how about:
CambriaCameo
CameronCamelliaCamryn KamaCarmenCarmela