I am just letting you all know of a relatively up-and-coming tracker for ebooks. They seem to be heavily concentrated in war-time and aviation-type ebooks however there is a wide variety there as well. They have a nice little community and the shoutbox is always moving.
Here are some stats on the tracker:
I believe it is still open signup. If not I will help you guys out.
Any question feel free to ask, I can field them here