Since a long time we need php5 with tidy and PDO. Until last week we was using:
deb http://people.debian.org/~dexter php5.1 sarge
But it stalled at 5.1.4
We decided to use the Source Package from bpo and modify the buildscripts. After some trouble in the beginning and reading of the Makefile, this wasn't really difficult to get it to work^Wbuild. The diff (without changelog modification) is available here.
You can also include this into you /etc/apt/source.list:
deb ftp://ftp.cyconet.org/pub/debian/cyconet/php5 ./