Z39.50 searches can take long when many different targets are consulted. The interactive process can be counter-productive in these circumstances. I wonder therefore if you too find batch Z39.50 searches an interesting idea: The user would be able to enter ISBNs (or other similar search terms) in a table, and koha would perform searches against Z39.50 targets in batch mode, either in the background, or semi-interactively, i.e. by taking-up a browser window. Search elements already processed, would be removed from the table, so that the user would be aware when the search is complete for each item. The user would also be able to add more search terms at the bottom of the list, even when the batch search is active.  Search results would be stored in an appropriate container (the “reservoir” perhaps) and koha cataloguing (cataloguing/addbooks.pl ?) would be amended to allow for searches against this container too.