Ah... Took me a while to find the feat I meant. It was in a book I least expected. Well close to least, Book of Vile Darkness would have been even more surpricing... Anyways, feat called Ancestral Relic from Book of Exalted Deeds. I realise that it wouldn't work exactly as written there but if you have the book, take a look and let me know what you think. It is basically like that Bonded Item, but you sacrifice items/money on enhancing its magic instead of XP.
EDIT: I decided to write it up in case you don't have the book. I don't know how infringing it is to post a complete feat but I hope it's ok, since I'm only giving out one...
Ancestral Relic
You own an ancestral heirloom and can invest it with increasing power.
Prerequisite: Any good alignment, character level 3rd.
Benefit: Choose an item you own. The item must be of masterwork quality, and it must be an item that once belonged to a member of your family. Alternatively, the item may have belonged to another person to whom you are somehow connected, such as another member of your religious order.
At any time, you may retreat to a consecrated or hallowed location and spend time in prayer in order to awaken the spirits in your ancestral relic. This requires a sacrifice of valuable items worth the difference between the market price of the magic item your relic will become and the market price of your current relic. This sacrifice does not have to be gold - you can sacrifice magic items or other goods worth the required amount, rather than selling your goods (at half value) to pay for the sacrifice. You must spend 1 day per 1,000 gp value you sacrifice. During this rime, you must spend at least 5 hours each day in prayer or meditation, not stopping to eat or rest.
For example, a 4th-level paladin has a masterwork bastard sword she inherited from her grandfather. She makes sacrifices worth 2,000 gp and spends two days in prayer and fasting in the temple of Heironeous. When she emerges, her devotion has awakened the magic inherent in the blade, making it a +1 bastard sword. When she reaches 7th level, she once again retreats to the temple for 6 days, sacrificing items worth an additional 6,000 gp to make her weapon a +2 bastard sword (market price 8,000 gp). When she reaches 11th level, she can make it a +2 holy bastard sword by making sacrifices worth 24,000 gp (the difference between 32,000 and 8,000 gp) and spending 24 days in prayer.
A character's level dictates the maximum value of his or her ancestral relic, as shown below.
No character may have more than one ancestral relic.
lvl Maximum Relic Value
3rd 1,350gp
4th 2,700 gp
5th 4,500 gp
6th 6,500 gp
7th 9,500 gp
8th 13,500 gp
9th 18,000 gp
10th 24,500 gp
11th 33,000 gp
12th 44,000 gp
13th 55,000 gp
14th 75,000 gp
15th 100,000 gp
16th 130,000 gp
17th 170,000 gp
18th 220,000 gp
19th 290,000 gp
20th 380,000 gp