Former Hawkins and Powers Aviation Inc's collection of firefighting and vintage aircraft at South Big Horn County Airport, Greybull, Wyoming. The firm went into liquidation and the whole collection is now for sale. List of aircraft as an excel (xls) sheet:
http://www.greatamerican.com/admin/uploads/events/711d08c1-e9e6-42c4-9872-4d2da4aa3ec4/Hwkins&PowersInv.xls
More info link has a pdf-brochure with fine photographs.
http://www.ruudleeuw.com/greybull-rp-may03.htm