Looking at dates for availability of stock for the new LG Nexus 5 goodies is pointing to early to mid September for a release. Some providers have a date of September 11th, although this would be no date to release the phone into the wild itself. IFA runs (officially) from the 5th to the 9th of September, so an announcement is likely here, followed by accessory availability shortly afterward.
This also indicates that it will most likely be the manufacturers themselves responsible for releasing the devices this year. Bearing in mind I've only seen leaks of stock for the LG device, if Hauwei are also to release a Nexus it would make sense to do it at the same time. Plus it'd give them some extra exposure to the market alongside the already well established LG.
So far, from leaks at least, both devices seem to have compelling shapes and build. I'm not going to regurgitate images here, because if you're reading this you've most likely seen them already.
Just a waiting game now.