I have to agree, I haven't seen any sidequests that offer EXP as reward. I just went to the first wiki site and looked down the list really quick, so this is by no means the definitive and official info, but it's pretty accurate: http://ffxiv.gamerescape.com/wiki/Ca...st/Level_50-59
There are multiple pages of level 50 quests on the site such as Main Scenario, sidequest, New Era, etc, and none of them seem to offer EXP as reward...
And if you want to convert EXP to gil ....... well, I'm against making botting more popular, which is inevitably what would happen (and you can't tell me there are no level 50 bots out there). There are already programs that go after closest targets in open world and FATEs. The added incentive of free gil at level 50 would not only drop RMT prices (enticing more people to buy, since gil is easier to get for gil sellers), but would also increase SE's work load of people CLAIMING others are bots because they stole a kill or staying in a single place "earning their money". Sure, you can call me a conspiracy theorist, but more of these claims to investigate would put more stress on the staff, resulting in either unfair banning results, removal of legitimately earned gil (which we've seen already), and/or claims going uninvestigated or unresolved due to how many there would be.
Think another ratio of EXP:gil would work? Even gathering bots can get to level 50 just by farming shards, and by equal rights, even gatherers should be getting EXP for each swing after level 50, right? More free gil for sellers.
No, I think SE has handled this as best as they could, as far as rewards are concerned, since I haven't seen any proof of any quests giving EXP. With the Challenge Log, there's more than enough gil fountains. The amount of level 50 quests aren't plentiful enough to have a direct impact on the game anyways, since they can only be done once per character.
TL;DR: Haven't seen any proof of sidequests giving EXP, and EXP conversions (in any tangible form) from other sources after level 50 is easily abused.