>    - Simplifying code
>    - Minimizing XML parsing

I had one patch with this which uses marc instead of marcxml from
biblioitems to provide huge performance improvement:

http://git.rot13.org/?p=koha.git;a=commitdiff;h=a18a7f709447cccf617e8fa5b545d6a82606deeb;hp=095b0af09d6cbc2bf579ba6ae353b9715b035118

(it needs cleanup, rebase and probably own bug)