Welcome to leatherworking.
Not sure without looking at it in person but those look relatively simple (not easy but simple). If the letters are recessed they are more then likely stamped and then painted. As far as the other parts it looks like they are cut and layered basically, use a different color leather underneath and cut holes in the top layer so you can see the other layers.
Those look machine stitched and that would be the easiest way but you could very well do them by hand.
As far as finding leather there are several suppliers. Tandy is a decent retail store, Springfeild leather (Kevin post here regularly) is great, waterhouse leathers, seigel of california, alot of these places will have plenty of types to choose from.
There was someone on the forum here who has made those and I dont recall who it is. Someone with a little more experience may be able to help out. Maybe do a search around and it may turn up. I think they made a few of these for the guys on there squad or whatever you all call it.