IN this mod you see the tornado pick up blocks and move them about, I am curious what is the function that renders some entity you can control from a block?

 

It should use the renderBlockByRenderType() method in RenderBlocks. If you surround this with the following code you can get every block in the game to render wherever you want.

Tessellator t = Tessellator.instance();
t.startDrawingQuads();
//The rendering code...
t.draw();

 

You can of course call this from a TileEntitySpecialRenderer or an EntityRenderer.

any good tutorial or explonation of it?

Spawn a custom entity at the block (look up entity tut.)

Delete block with world.setBlockToAir(x, y, z);

in your entity render file, call the above code.