Look at Monte Cook's Book of Eldritch Might III. It has a really nice chapter that reworks the intelligent item creation rules. The short of it:
1. Spend gp and xp for each point of the attributes.
2. Spend gp and xp for each xp the item has (keep reading).
3. Depending on the level (from xp) of the item, that determines the abilities it can have. (1/4 the normal amounts).
4. Spend gp and xp to add abilities.
It makes things make a LOT more sense.