Hi Pierre,
Thanks for your kind comment about Icy :)
There is already a batch processing feature in the Spot detector plugin so it can handle a group of file or a directory but there is nothing like that for the track manager.
Indeed we plan to add block for the spot detector, and now you are talking about, it is important to include the particle tracker too in block form, it can export its result in XML format in a specified directory to start with.
Right now, you can still develop your own Icy plugin in java which just make the batch processing.
If you are interested in that solution, i highly recommend you to use Eclipse with the Icy4Eclipse plugin :
http://www.herve.name/pmwiki.php/Main/Icy4Eclipse
Then have a look on this documentation which provide basics tutorials :
http://icy.bioimageanalysis.org/index.php?display=devDocCheers,
- Stephane