I have started doing the quests again on a different account. Just finished all the quests on the Shuffle Island and got 10,000D in total. I realized that I have missed some quests the first time, as some quests only pop up after some other quests has been completed. Gonna do Clannad and DC next, then after that I'd probably pop back on my main account to do the quests that I missed.
Update: Just finished the quests on Clannad Island as well, got another 10,000D. I'm guess if not missing any quest, should get 10,000D from each of the Islands. I'll confirm this when I finished the quests on Da Capo Island too.
Update: Just as suspected, Da Capo Island also give a total of 10,000D.
I already blow all 30,000D on the D Ai PON machine that cost 2,000D each play (15 times), but gotten tones of nice stuffs:
