How to break out SMD chips in-circuit?
Depending on how stable you are looking for, you may look at the example of "Bunnie" Huang's tap for the Xbox.  This was to tap a 200 MHz bus to memory.  He did this with a small PCB, one side shaved at an angle epoxied to the motherboard.  By wicking solder between the exposed traces of the motherboard and the card.

The picture of the motherboard you posted doesn't have the nicely parallel top-layer bus, but I thought it was a neat idea.




  The Tap Board has on one edge a pattern of traces with no soldermask
  that matches the pattern of traces on the Xbox motherboard. The Tap
  Board was soldered directly to the Xbox’s northbridge-southbridge bus.
  Only the receive-direction Tap Board was mounted for this study. The
  mating edge was shaped using a belt sander, so that the tapping traces
  were flush with the edge of the board, and the board could be mounted
  at a reclined angle to enhance solderability. The soldermask on the
  Xbox was removed with fine-grit sand paper, and the Tap Board was
  carefully aligned by hand, and then held roughly in place by soldering
  a coarse piece of wire between the Tap Board and the motherboard. A
  hard-setting adhesive, such as Miller-Stephenson Epoxy 907, was
  applied to fix the angle and mating distance of the Tap board to the
  motherboard; once the epoxy was cured, the holding wire was removed,
  and the traces between the Tap Board and the Xbox motherboard were
  easily soldered using a fine-tip iron and a microscope.


from Keeping Secrets in Hardware: the Microsoft XBoxTM Case Study, Page 7 by Andrew “bunnie” Huang



On the commercially available side of house, several companies make TSOP probes for a pretty reasonable price for commercial work (~$800).