> > using a random seed e.g. a value derived from current time stamp
> 
>   Pay attention that current-dateTime() is stable.

Yes, I know it's stable. 
That's why I suggest to use xslt generator function, which isn't stable.
The task of creating of pseudo random seqeunce requires: random seed and a 
sequence numbers. These two things are in hand.
--
Vladimir Nesterovsky
http://www.nesterovsky-bros.com