It seems I've come late to the party
Anyway, having been to Topkapi several times, I can say for sure that not all the relics were brought at once, when it was completed. So its definitely the case that you could have a UHV following that, but set it to be completed in 1600, (1595 was when the Holy Banner was eventually captured by Mehmed III and displayed in Topkapi.
A UHV could be something like have x amount of relics in Istanbul and complete the Topkapi Palace.
Here is a list of more relics placed in Topkapi, as there are sure quite a few of them, and definetly more could be added!
http://en.wikipedia.org/wiki/Sacred_Relics
Perhaps you could even add to the Topkapi power to give as well perhaps 2 extra gold and culture for each relic placed in the city.
Also the "Head of John the Baptist" relic is nowdays in Damascus in the Ummayad Mosque. In fact in 2001 I believe, Pope John II went to visit it. Shouldn't it be a Muslim relic since they covet it just as much. I mean, the problem with your relic list, is that some relics can be used for both Muslims and Christians. Also it would be interesting if you made more relics, but had them religion specific, for example only Orthodox or only Shi'ite relics. That would be interesting.
Also any thought about Hindu/Buddhist relics? Perhaps the tooth of the Buddha. Here is some information for Buddhist Relics:
http://en.wikipedia.org/wiki/Śarīra
Although I couldn't find much information on Hindu relics....
Also I agree that relics should be slow and easy to capture by enemies, such as spy's. Although I would doubt the historical accuracy of any spies, or mercenaries ever capturing relics.... but nonetheless it would be super cool!