Why not just get the HP replacement?
Did you try http://www.pcpowerandcooling.com ?
And many power supplies will have connections you won't use. This bothers some. Others will know that you can't make power supplies cheaply unless you consolidate the models.
I'm looking to replace my hipro hp-1603a3 power supply but I can't find anything close. Do I need the p7 and p8 connectors? Is the p6 for a floppy? This is hp part number 5185-2917. All the micro ATX power supplies that I look for have only a few connectors.