Hi @robbiegregg, if you are daring enough to open up your Egg (not really that big a deal), by unplugging the USB cable you can make room to insert a microSD card into the slot. With that in place, you can put the Egg into an offline mode (opmode offline) in which case it will write data to the SD card and you can download it from the device later. We have an offline data logging package that adds RTC hardware as well.
I'm working on adding NTP capability to the software for a future release (Version 2.0.6), so that time stamps are more meaningful (i.e. without an RTC installed, and assuming you have Wi-Fi available).
Not sure this is what you're getting at or not, but maybe it will be helpful to you.