Just wondering if you could post a screenshot or two of the new client... if that is possible at the moment. I am very curious to know how will it be like.

Unfortunately that is not possible. The GUI will be one of the last things to add, so there is nothing to show at the moment.
However, you (or others reading this) may not be aware of the external third-party helper application for the current simulator that allows some GUI type access (
http://www.rechenkraft.net/download/evohomegui/evoGUI.htm) programmed by Michael Reich. The corresponding screenshots are most probably not representative of a future EaH-GUI though.
And I know that its better not to post launch dates, because there's always delays, but could you tell us for example in percentage how much is it done already? 70%? 80%? maybe more...?

If I could say that I could as well post a lanch date. It is not meaningful to give a percentage, because it would only be the percentage of the things that I currently see. But the things that I don't see determine the real progress.
For example, I have written up some of the results of the current simulator and I am in the process of submitting them to a scientific journal - something that is vital for the overall progress of evolution@home. However, I have submitted the same story to other journals before and each time it was rejected for reasons that prompted further improvement to the report. How will I know it will be successful this time or how many changes are still required?
Since publication of results is essential on the long run, this is what currently takes up most of my time:
a) publishing biological results that follow from already completed simulations of Simulator005
b) publishing biological results that point out the limitations of current theories and that justify development of the biological side of Simulator006. After all it is in everyones interest to have simulators that are focussed on the things that are really unknown and that do not spend a lot of effort to compute what could have been predicted by a simple formula already.
Once these publications are off my desk, I will be able to focus more on the programming aspects that result in faster visible progress from your perspective. I know that the wait is long and difficult (I personally feel the same), but I believe that it will be worth while.
Thank you for your patience.
Laurence