Got a suggestion- forgive me if it has already been done I'm new to the forums- 
An interactive system for the TARDIS flight inside would be interesting, individual controls perhaps i.e. handbrake, throttle, zig zag plotter, scanner, helmic regulator and stuff maybe in flight combat, daleks and such attacking the tardis, regeneration... The possibilities are endless, cities on gallifrey with timelords who can trade, you could add quest systems, god there's so much you could do lol 

Just to let you know, it's been confirmed that  many of the individual parts for the Toyota/Coral console have already been modelled and are planned to be added into the mod. If it helps, I know John will make a special update just for Regeneration, so you can regenerate 13 times per world.

 Wait... Isn't the regeneration cap 12? (13 bodies, 12 times regenerating)

 By the way, Trading with time Lords, I love this idea. Imo, they should have unique trade options. Nothing Villager like but stuff a bit more.... Gallifreyan (Just not Tardis Parts... I mean really. What fun would that be. Plus in regards to Time Lords' general time traveling policies and just plain realism, why would every Timelord have access to Tardises, let alone be carrying around parts of them? Lol)

Thanks for clearing that up regarding the parts, I'm new here lol. Although I played the mod before it was quite early days lol and I've not used this site before really. The whole Gallifrey thing could be used amazingly :P

 Definitely. I thought of a rather funny one XD

There can be a Time Lord with Very Curly hair and clothing based on the clothing the Doctor wore in Deadly Assasin (Or was it Invasion of Time?). This TIme Lord has no name but is known as "The Jelly Baby Merchant". He gives a player a free bag of Jelly Babies on the first encounter of one in a Citadel and further Jelly Babies have to be purchased. He's a rare spawn, and the spawn cap is 1 Jelly Baby Merchant Per Citadel.

He's meant to be a reference to the fourth Doctor, but whether its actually him or not is unknown.

He will use a few stock phrases from the fourth Doctor as his audio.

(Actually, I may post this myself as  a suggestion soon. Not the Trading idea, but the merchant himself)