Oh my gosh, it is absolutely what I am looking for! … almost.
Sadly I have to start with demands (or wishes if you will

) right away: There absolutely has to be a landscape mode. Next, the date has be removable or off-turnable in order for the clock to be full screen and thus as big as possible (my eyes are not that good and I would really like this). Lastly, if there is a date, then you must provide us with a way (for instance via a txt file) to set our languages labels for month and day names.
And about the discussion with battery life:
I searched the internet and came up with a Kindle Touch test, which said with a full charge the Kindle holds for about 45.000 page turns. Now we divide this through the number of minutes per day and get 45.000 / ( 60 * 24 ) = 31,25. O_O
So with a full charge, your kindle can be a clock for a full month!!! OK, let’s say a full page refresh only happens every 6 pages, but that still leaves 31,25 / 6 = 5,2 days. Though you could optimize the screensaver in various ways, like always only partial screen refresh, and have a configurable battery saving mode (for instance during night refreshing only takes place every 10 min. or so). Of course you also have to subtract the actual reading, but I think at least one week with a full charge should be no problem.
So what’s with the whining about battery life, everyone?