Re: Starting my Doctor Who sonic collection....
I just received my "Other Doctor" sonic, by CO. And I've got another tenth Doctor sonic coming, to have as a "9th Doctor", since the older Eccleston ones I've found seem to go for about $80.
I finished my display- for the most part. Prototype stages, if you can call it that.

Sneaking big pieces in and out of work gets stressful, and I made a few stupid mistakes- as you can see. But with the sonics in place, you can't even tell.
The base is black Delrin, with a Lexan back, and top support. Not quite what I wanted to do, but I'm still in the tweaking stages. I had to move the bottom holes another 10mm forward- the Pertwee and Baker sonics wanted to fall over. So a 20mm lean turned out to be the charm.
I'm still waiting on them to release the 5th and 8th Doctor sonics, and I even left a space in my display for the Colin Baker "sonic lance", should they decide to do it.

I also left room for the (presumably) Capaldi sonic. Though those are just smaller pilot holes, 'til I know the diameters to cut.
And yes, I know the Tennant sonic is extended- I like it that way.

Makes sense to me. Better symmetry.