There have not been new version of ebuild for dev-php/ZendFramework for a few years. I was using old version all the time because I thought that Zend stopped to release new versions of ZF 1 because there was not update in portage. Currently upstream there is ZendFramework-1.12.5 but in portage there is ZendFramework-1.11.12 which is quite old. I have copied "ZendFramework-1.11.12.ebuild" to my local overlay and changed it name to "ZendFramework-1.12.5.ebuild" and it installs and works great. So I don't see why not add it into portage tree.
*** This bug has been marked as a duplicate of bug 448576 ***
It is not duplikate because bug 448576 concerns ZF 2 which is not in the tree. My request concerns ZF 1 which is in tree. ZF1 and ZF2 are two different libraries.