Starting with a new cockpit, it may seem as a very big problem to get all the measurements you need. And it is! Most detailed information is hard to find, expensive or classified. There is  however a whole range of options that you have, to gather information on measurements, real parts and even operational procedures. 

I will use the building of a military cockpit as an example (since I have some personal experience in this), but for any kind of cockpit there's a similar alternative (mech-pit builders may disagree on this ;-). 

This list is by no means complete, nor is it meant to be. If  you come up with another source of information, please don't hesitate to let us know!

SimPits Website

First of all, of course, browse the SimPits website. If you don't find what you are looking for, by all means contact anyone of SimPits or even better, join the SimPits mailinglist and place your request there. The members of SimPits have quite a library of information all together. So if you can't find it, ask for it.

EBAY

Http://www.ebay.com is an online 'auction' site. Absolutely one of the best places to look for flight-manuals, models, accessories and even complete cockpits on sale! Check it regularly, because new products are added  by the hour!    You can also check the internet for other auction houses.

Museum

Do you have a (military) aviation museum nearby? Don't hesitate to contact them and see if they can help you. A lot of museums have a big library of technical data of the aircraft they have, including flight manuals and technical drawings. A lot of  personnel working in these museums are aircraft-enthousiasts just like us, so they might be willing to help you out if they can. No drawings or measurements? See if you can at least take a lot of pictures of the cockpit you plan to build.

Military Airbases

Some military airbases are willing to help you on your quest for information, although it must be said that most of them are not very enthousiastic about bringing out any information. Do you have a friend or relative working there? See if he can do something for you. At least you'll know you'll be getting the most up to date 'de-classified' information from there!  You can also check out other military organisations that may be able to help you out.

Plastic Models

Maybe not so obvious, but plastic models can also be a good reference for measurements. Of course, depending on their scale, they're only good for rough/large measurements, and you must keep in mind that not all models are perfectly detailed, or perfect in size. The bigger the model is that you can lay your hands on, the better, but that should go without saying. Which brings us to:

Local Hobby Shop

Found a shop that sells your beloved plastic models? Some of these small 'hobby-shops' also have scaled drawings for the 'hardcore' modellers. Ask them if they can help you, and if not maybe they can tell you where to continue your quest! You can also check out local RC Aircraft organisations or organistions like the IPMS (International Plastic Modellers Society)

Aviation shops

Some aviation hobby shops that sell (salvage-) parts of aircraft, also have detailed documentation on these, or other aircraft. Check them out, and if they can't help you, they might be able to help you with a better address or let you measure and photograph the stuff you don't want to buy.

Airshows/expositions

Some, if not most airshows, have stationary aircraft on display. Mostly you can't get too close to them, but sometimes you can. Take your measuring ribbon and sart taking pictures and measurements untill you're kicked of the property. You could of course also ask nicely ;-)At some airshows there are actually separate cockpit-sections on display. You have to be lucky though...

Library

Your local library could be a great source of information, althoug most libraries don't have a very large collection of books with scaled drawings of contemporary jets. It's worth checking out though, you never know what you may come across.

Salvage Yards

A salvage yard with the jet that you want to model... Hmmm, isn't that a SimPitter's wet dream? ;-)  If it does have it though, it would be close to the best thing you can get for taking measurements, or you could buy the cockpit, just like that ;-)

Flightsimulation Museum

A bit of an obvious choice maybe. But do check out if there is such a museum in your neighbourhood. If lived 10km near one all my life, and only found out a year ago, so.... With a bit of help of the people working there, you can actually find out a lot more about simulation itself!

Browse the internet....

I don't think this one needs any further explanation... ;-)