With the bow tie it was either him or Patrick Troughton.
The process of making this head involved getting some reference pictures online, importing them into Blender, doing some rough shaping, and then using Blender's sculpt tools to finish the job... or so I thought. But the roughs looked enough like Matt Smith to me at least in Blender, that I skipped the sculpting stage. Besides, this was for a tiny head, a lot of detail would have been lost.
Unfortunately the print turned out to be only suggestive of Matt Smith in the end, not entirely a bad thing, but not as good as I was hoping for. But at least it's not Tardimus Prime any more... eech, that's a terrible name. Optimus TARDIS? TARDIS Prime? Yeah, there's no good way out of that one.
There's another TARDIS transformer that I thought would be a good candidate for a David Tennant head but I'm not really thrilled with that one. On the one had it's K9/Lazerbeak is cool, but the way it assembles doesn't seem as friendly to me as the other one. And, really, do I need 2 TARDIS transformers? (Or do I really need 11...?)