hayhay,
Your questions are kind of like asking how to build a car from scratch. But if you really want to build something elaborate in the basement get ready for some serious learning and based on what you said about having some of the elements ready to go so you don't have to go one switch at a time - it will ultimately mean a serious cash outlay over the coming months and years.
A great place to start is a site dedicated to those with the home cockpit building fever and that is:
mycockpit.org
They have articles on things as basic as how to put a budget together for your beginning project. Besides AVSIM forums I spend time at mycockpit.org
I would say the one of the great things about this hobby is you can start as basic as you like and then get as elaborate as you ultimately want and can afford to go including a full cockpit in the basement like you mention. Obviously the more realistic you go - the bigger drain on your bank account.
There are many companies out there that have components for the pits ready to go. You can spend from a few hundred dollars up to several thousand dollars for components (like overhead panels for the 737) and everything in between. Lots to learn but lots of options and for most I think it can be a very rewarding hobby. Good luck, however you start but the site I list above as well as the amazing guys on AVSIM forums will help you learn along the way.
Also remember you can go in phases and learn things like spreading your processing and add-on load across a multi-computer network, then add multiple monitors etc. etc. (not necessarily in that order, but you get what I mean) You'll have fun no matter where you start. I'll get out of the way and let the experts chime in. It is all about fun even through the frustrating times and then enjoying the sense of accomplishment as you build from simple to more complex. Cheers.
Tim Pfohl (jet21)
