Look at the bell in the Lego kit for Big Ben (#10253). Building instructions are here (Step 276).
The bell itself is made from several round plates and parabolic reflector dishes. It's not hollow, but it could certainly be made to swing.
Your question sparked an idea of making a completely symmetrical 6x6x6 cube with the same tile on each face.
This is what I came up with:
The LDCad file is here.
I used only parts available in LDCad version 1.6b
Yes. 1x1 Brick dimensions are 5x5x6 units. 1x1 Plate/Tile dimensions are 5x5x2 units. Since we have the top surface measured 2x2 studs, this brings us to top with 10x10 units in size. From here we need to construct a side of 10 units too. Taking out top and bottom tiles (10-2-2) we are left with 6 units, which is exactly a height of a brick.
Here's an ...
I had a whole bunch of pieces that were flat, 2x2 with studs on both sides. They were not actually LEGOs but some knock-off brand - I want to say Tyco? Not sure, it's been a while, but it was 100% compatible. I used them for this sort of thing all the time. It annoyed me that there weren't any official LEGO pieces that served this purpose at the time, ...
As mentioned in another answer, there are dedicated pieces for this now.
But... 6x6x6 cube is plenty big enough to have a stud-reversing construction inside, then the bottom can be a simple 6x6 plate with regular smooth tiles.
For example put some of these inside the cube:
While there could be various approaches building studless the easiest one would be with Tile, Modified 2 x 2 Inverted. These modified tiles have studs on one side, which fit under bricks and plates, and smooth surface on the other side.
Here is a prototype which features equal 6-stud (or 30 modules) long sides. Parts can be changed upon availability, but it ...
Any Technic brick (or combination of several) with 3 or more holes on the side. Technic, Brick 1 x 4 with Holes is a best single piece that can be used to attach skull without any holes being visible.
Technic, Brick 1 x 1 with Hole + Technic, Brick 1 x 2 with Holes
Or two of Technic, Brick 1 x 2 with Hole
If you need anything without ...
I'm afraid you cannot pass a bar through dome version you are interested in (actually any of the versions of this dome as they all are blocked one way or another) as seen in this picture from Rebrickable:
However, you may consider Brick, Round 2 x 2 Dome Bottom which does have an option to attach bar through it.