Any thoughts as to where the Ark of the Covenant is now?
The earthly ark of the covenant was based upon the pattern of the heavenly ark of the covenant and that one is apparently still in heaven:
Revelation chapter 11 verse 19
And the temple of God was opened in heaven, and there was seen in his temple the ark of his testament: and there were lightnings, and voices, and thunderings, and an earthquake, and great hail.
The temple in heaven is also called
the temple of the tabernacle of the testimony in that God referred to what was placed within the earthly ark of the covenant which, again, was based upon the true ark of the covenant in heaven as the testimony:
Revelation chapter 15 verse 5
And after that I looked, and, behold, the temple of the tabernacle of the testimony in heaven was opened:
Exodus chapter 25 verse 16
And thou shalt put into the ark the testimony which I shall give thee.
Wherever the earthly ark of the covenant is, I suspect that it will show up in the last days and that it will be a part of a rebuilt Jewish temple in and about where temple sacrifice will be restored prior to the return of Christ as Israel's final affront towards God in their rejection of Christ and His atoning sacrifice.