Not in shop rewards for X-amount of housepoints

I thought, to promote making homework or grading homework, there could be only optained items as an reward when you reach x-amount of points in a year.

For example, when you reach 100 points. You get a rubberduck-hat! Who you can't buy in any shop.

Then, when you reach 225 points. You get a special map of Hogwarts! Who also can't be bought.

And for example the highest reward at 500 points. You get a portait of dumbledore! That you really can't buy in a shop.

Those are just a few examples. There are a few special optainable items for VIPS. Maybe, we can make some more for those point-rewards?