This is quite interesting and brings up a number of points beyond your initial example.
First of all though, I think the statement that you can only have one ancestral item is going to be a problem as pointed out earlier. The DM will just rule as he wishes and he would not be techniquely wrong. If I had a apartment lease that read you may only have one pet, I would not assume that means you can only have every had one pet in your entire life or you cannot move in. But that is just me. Also the word have instead of own is interesting, someone else can have an item without owning it. Again, I could have an appartment, but no own it. Although I don't think you could take the feat more than once and the feat clearly applies to a single item (not counting the warblade example).
The main thing that struck me was that it does not state anywhere that the item losses it's bonuses if lost by the original owner. These means retraining or feat shuffle tricks work just fine on the feat after you are happy with the current level of enchantment on the item. Wether or not the item is still an ancestral object could be debated.
Part 2, it does not state the item does not work for anyone else. This I find interesting because of my favorite use of this feat, tomes. At high levels the feat gp cap allows for +5 inherent Ability Score tomes. Once you read the tome, the value of the object drops back to its base value. Enchant, read, and repeat. You can effectively buy tomes at half price or less (assuming you take unwanted items that were to be sold for half price as your share, and that you dont sacrifice piles salt from wall of salt spells to make the item). Even party crafters won't want to make tomes due to the xp costs. This means you can extend the use to other party members, assuming you have the necessary time to enchant (a problem with all crafting). Ha, of course you could maybe work in a single use twin, repeat wish scroll effect + 1 additional wish to get a +5 for less. Other good use of course is for your archivist. A book of spells does have a gp value and it can be a magic item (or just put scrolls in it and write them to your spell book, risen repeat).
You could likewise have a cohort select the feat and give you the item. Or in the example of tomes, have your cohort at home on your demi plane of fast time with the cash and item enchanting it up.
I would be afraid of trying this with an item familar granting xp though... unless you want to bring the thought bottle into the equation destroying all hopes of a reasonable game. How does this work with the chameleon mentioned earlier though? You must invest life energy by level 6 and chameleon bonus feat kicks in at level 7. Early entry tactic that can boost your cap on two skills or fun with negative levels? I am not sure if Invest Life Energy counts as a calculation described by negative energy. But I guess you could pick a an item that grants a negative level while holding it, invest life energy, though bottle it for a 10% boost on all xp -500 for thought bottle storage, remove feat, restore xp, and repeat the process ad naseum.
