Hello everyone, since my last update I fixed some bugs about upgrade and some strings for update the mysql.
Finally, I can say that the speedup wasn’t much superior, maybe get the lft and rgt values in the sql queries add more time in the process. But I have a good news, the speedup in Edit Pages section in admin panel have a good acceleration, see the chart: http://spreadsheets.google.com/pub?key=tvUiOf6bEO5A55cMLjbDTdw&output=html
The last patch is in http://dl.getdropbox.com/u/173207/diff-20090817.patch . Remember, only apply the patch on a test WordPress installation.
Thanks to all, these months were really good .