10/10 update:
rnc hid 3 more tardises today under the same rules

Tardis 5:
Prize: 10 diamond blocks
Winner: cepheid
Picture:

Tardis 6:
Prize: 10 diamond blocks
Winner: CovertRaw
Picture:

Tardis 7:
Additional hints: the closest one to spawn so far, and for the first time no ender pearls are needed
Prize: 15 diamond blocks
Winner: CovertRaw
Picture:

Thanks again to rnc for hiding the tardises, and for everyone that participated, I had a blast and finally found one for once :D

the tardis is always the same color idk if they are only 1 color

Why am I always doing homework when the tardis hunts are going on!? D:

sigh i missed these three ;-;

Wblaine pranked
http://prntscr.com/ctrsb1

BREAKING NEWS: new tardis spotted at spawn

Tardis 8:
Additional hints: none really
Prize: bragging rights
Winner: wblaine128 (Qfu in spirit)

This one was fancy. I recommend looking for it!

Tardis 9:
Additional hints: what?
Prize: 10 diamond blocks (given by cepheid)
Winner: Cileklim
Picture:

Love doctor who, loving this server more and more. Congrats to all winners

Tardis 10:
Prize: 15 diamond blocks (upped from 10 to 15 after some time had passed)
Winner: cepheid
Picture:

Tardis 11:
Prize: 15 diamond blocks + a tardis built by rnc2011 in your base
Winner: cepheid
Additional note: no ender pearls were needed for this tardis, although we didn't know that when searching
Picture:

Picture of prize:

You got a tardis of your own? lol
so jelly right nao

Great. Now everyone will be on the hunt for the tadis in our base. =P

Tardis 12:
Prize: 10 diamond blocks
Winner: sirchristopher10
Picture:

@cepheid Tardis 12:
Prize: 10 diamond blocks
Winner: sirchristopher10
Picture:

no pic is there

Tardis 13:
Prize: 15 diamond blocks + a redstone torch signed by rnc2011
Winner: cepheid
Picture:

Picture of prize: (including a typo in the date :P)

ayyy it's me in chat
always remember to watch the caps.

@Cellexya ayyy it's me in chat
always remember to watch the caps.

lol

Tardis 14:
Prize: 10 diamond blocks
Winner: CovertRaw
Additional note: no ender pearls were needed for this tardis. This is also the one players will be most likely to find by accident :P
Picture:

Shout out to @Dan0ze who found the tardis before rnc finished it :P

Tardis 15:
Prize: 32 diamond blocks (was 20 but I decided to increase the prize once I was how insanely difficult it was to find)
Winner: awearasp12
Additional note: this one took at least 50 minutes to find, and is far and away the most difficult so far
Picture: