Both setups are essentially piecing together miscellanous parts. The granada swap would be easier, you find a granada at your local junkyard and pull everything off of it, from tie rod ends to the calipers. The scarebird is similar, but they use other parts look at the bottom of this page to see what they use
http://scarebird.com/12802/19004.html . The assumption is that you are going from an all drum setup to front disc rear drum set-up. To save yourself on the hassle, go buy a complete kit from one of the known companies. There are alot of parts you need to run front disc, especially if you want power brakes.
You can always find a decent deal from people putting sets together on ebay, likes this one
http://cgi.ebay.com/ebaymotors/Musta...13222151QQrdZ1
There are alot of sellers on there with sets similar to this.
My opinion is that if you can save the $500 to piece together a set like this, just wait and save the other $500 and order teh set from National Parts Depot (or other mustang part retailer). If you are going to do it, do it with quality parts, Your brakes are a very important part of your car.
-Edgar