Just found this on an adoption website:
"Older persons, who may find domestic adoption presents too many hurdles due to the age factor, often turn to countries like Mexico, Russia, or Greece where the upper age limit is 60. Other countries, like Ukraine and Venezuela, have no statutory age limit; however, prospective adoptive parents are interviewed and their abilities to parent evaluated." Also I read that Ethiopia has no legal age limit, although generally places children with no more than 40 years between child and parent - would you be willing to consider an older child?
Hope this helps...