I've talked about this before, but I'm still fascinated by the whole idea of the old testiment ark of the covenant serving as the literal throne of Christ.
The one called Mercy WILL take a seat on the Mercy Seat!
We find Rev 4:5 says this about the throne,"And out of the throne proceed lightnings and voices and thunders"
In Rev 11:19, it says this about the ark, "and there was seen in his temple the ark of his covenant; and there followed lightnings, and voices, and thunders"
If you can put 2 and 2 together you can almost come to this conclusion that they are talking about the same thing.
Another theory I have is that it is in Ethiopia. In Isaiah 18:7 it says a gift will be brought to mount Zion (when Jesus has returned). I can't think of any gift that would be worthy to be in the temple besides the throne or the ark (or in my case both). It would likely be considered an idol if it was anything else and would not be worthy to be before Him.
Now the way we traditionally see the ark may not be the way it actually looks. I believe it looks like an actual seat. It's all in how you interpret the description given. If I could describe how I believe the ark looks, I would say the Cheribum's wings are touching on the back of the seat (like the back of a chair) and the other wing is laid on top across where you would sit. It looks like an actual seat or throne.
What a beautiful picture to have what was once a cloud presence above the ark, now the presence of God in the flesh sitting on top of it. It drives me to fascination!