Pogo Pins for 1.5mm Pitch Test Fixture
There are few companies which make pogo pins for such small pitch. you can use a 1.5mm crimp housing connector as a quick hack, slide the pins through it and you have a ready made 1.5mm  pitch test jig. However, a better approach would be to arrange the pins in a zigzag pattern (might not be possible in your case).
Here is a 1.27mm pitch pogo: http://www.idinet.com/Test-Probes/Loaded-Board-Probes/ICT-Advantage/ICT-50C.aspx/