There are no shops that sell "ready to install" Linux CDs for AmigaOne or Pegasos. In the case of the AmigaOne, you get an AmigaOne-specific install CD, for either Debian or Yellow Dog, then you go and buy the PPC Debian or Yellow Dog CDs from any vendor you want, or get somebody to download and burn them for you. Probably Pegasos is similar.
--Eric
