Brazil
has had 4 KC-137s... B707s converted to aerial refuelers with wingtip hose pods (only 3 active as of March).
In March of this year they signed a contract with IAI to convert 2 (or 3, the article below says both) B767s to aerial refuelers, also with wingtip pods. Talk about a timely contract!!!
IAI to Convert Two Boeing 767 Into Flying Tankers for Brazil - Defense Update - Military Technology & Defense News
I guess we know which will be the first KC-137 replaced.
Brazilian KC-137 crashes on take-off in Haiti, none injured