This Berkshire was just listed Sunday on Detroit area Craigs list and sold that day for $1000. According to the previous owner, the new owner indicated he wanted to add it to his collection, but has placed it on e-bay. According to the original owner the motor is frozen, but that is not stated on the e-bay listing.
http://cgi.ebay.com/ebaymotors/Other-Makes-PENTON-SIXDAY-BERKSHIRE-100-1974-PENTON-BERKSHIRE-100CC_W0QQcmdZViewItemQQitemZ320360380357QQsspagenameZRSSQ3aBQ3aSRCHQ3aUSQ3a101