AVR-Chat

You could use pogo pins like these
http://www.mill-max.com/images/products/pdf/121.pdf

I would use this part  0922-0-15-20-75-14-11-0 it is available at
mouser as PN 575-922015 for $0.48 each. 
http://www.mouser.com/search/ProductDetail.aspx?R=0922-0-15-20-75-14-
11-0virtualkey57510000virtualkey575-922015

You would only need a miximum of 10 to even do JTAG debug.

These could be mounted in a proto board and have your UUT push down 
and contact the pogo pins. These pins do require 100 mil spacing.
But all you would need to do is add test pads where you could on the 
bottom or top depending on which is easier to accomplish.

We make this type of adaptor for several CCA's with very good results.

Dyan...