http://unicow.cloudapp.net/
I have created a very simple cloud application.
It can give back a GUID or a UTC date/time on proper ISO format.
If I have the time I will update it to be formattable and to give back consecutive numbers for a project. The URL would then be something like http://unicow.cloudapp.net/DateTime/yyyy-mm-dd and http://unicow.cloudapp.net/Teller/MyProject Future updates might include XML and Json too.
Since there is no HTML it should be easy to use from clients.
It is just a temporary Azure account so it will vanish by itself when time comes.