Alexander & Odin are summonable in FF11. It was quite a ways into ToAU's lifetime though. They are only active during 2-hr and don't last long. Was a bit lame, but they have their uses.

In FF11 they follow you around, but what if for FF14 anyone could summon (like some FF's) where they appear for a short time, do something, and then disappear (i know pet class enthusiasts would hate this)?