I had the same experience. The 16 GB went first, then the 8GB about 20 - 30 minutes afterwards.
I expect LG will be able to make more, but this is a standout phone.
In my case, my Nexus 7 basically opened the horizon up for me, as far as moving from my iPhone 4S. The fact that T-Mobile hasn't yet marshalled many towers to support 3G on the iPhone 4/4S makes the switch to a pentaband phone a real plus as far as utility is concerned. Edge works, just, but really sucks every day.