In fact I want to be able to read PDF document because I would use it (like the author of this thread) to read scientific papers.
But I am still thinking about this: Finally, except for the autonomy (which is not great for the DR1000s anyway if I've understood well), why not to buy a HP TC1100 for about 350€ (or 450$) (
http://www.tabletpc2.com/Review-HPTC1100.htm ) ?