If somebody is obese and had taken a lot of fat soluble vitamin d, will he "get" too much vitamin d if he loses weight while the fat dissolves away?

Doubt it: Unless you have 1, 000 pounds to lose, it's highly doubtful that you have enough vitamin d stored in your fat cells to cause any problems while you're losing weight. Obesity is far more dangerous than anything vitamin d could do to you anyway.

No: If you continue to take the high dose vitamin d replacement while losing weight, you could have higher vitamin d level. What you had already taken shouldn't be a problem when you start losing weight. Your level will not go up.