I've prepared a couple ideas for future TARDIS exteriors, all of which all ready exist in the game and/ or The Dalek Mod.

Crafting Table

To go side-by-side with the recently added Furnace TARDIS, A Crafting Table is the next logical choice to add

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PS. I use a resource pack called Sphax PureBDcraft... I havent actually ever played with the default resource pack, so I have no idea if this would work with the default crafting table...

Server

The also recently added Server decoration block look perfect for a TARDIS too!

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Television

Another recent addition to The Dalek Mod and another perfect opportunity for a TARDIS Exterior

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These are some super quick screenshot edits using photoshop. Not my best work, but I hope it gets the point across

I was literally about to post something about how it would be cool to have a server exterior and then I saw your thread. So I'm 100% with you for the server idea. Plus, the crafting table and television exteriors are also really cool!