Hi Alaska -
Dave has suggested a couple of possibilities. Other text transitions that sort of "tumble in" are wave & windshield.
All the text effects in PD8 are 2D. What you're talking about sounds like it needs 3D animation... and to do that, you need to look beyond PD.
Gimp is open source software that would be useful to you. There's a downloadable script for a spinning cube at
http://fence-post.deviantart.com/art/GIMP-Spinning-Cube-Script-74111738 (too technical for me).
If you wanted to follow that path, I'd suggest building it on a transparent background so it can be used in a PiP track without relying on ChromaKey.
Cheers - Tony
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