The solution may be to search where there is "nothing" visible
Some members of the SETI community are trying to convince the
rest to stop searching just Sol-type stars for signals. Our best bet
may be those objects which only appear in the infrared region of the
electromagnetic spectrum in the outer, colder regions of the galaxy.
See here for the details:
http://arxiv.org/PS_cache/astro-ph/pdf/0506/0506110.pdf
Fermilab is conducting searches for Dyson Shells using the data from IRAS:
http://home.fnal.gov/~carrigan/Infrared_Astronomy/Fermilab_search.htm
Also see Robert J. Bradbury's Matrioshka Brains:
http://www.futurehi.net/docs/Matrioshka_Brains.html
