Currently, China site DIY Netcom has supposedly got their hands on the engineering samples of Haswell, and successfully started it up on their system (Which probably means they have a Z87 board as well). For the upcoming days, we will be expecting news and benchmark results from the Core i5 Haswell.
This processors are marked as "Engineering Samples". They are clocked at 2.6GHz, but previous leaked specifications charts does not have any models with a base clock of 2.6GHz. This means that this could be a very early sample.