Probably relevant for me to post this since you bring up the OST for Lain. I've been covering stuff on guitar for youtube videos for years (on and off) and the Lain OST is one of the things I've focused on doing. I'm modest about it, so I'm weird about using the youtube tag to link, since it would make it so big and attention drawing in this post, so I'll just link normally to the Lain's Theme video. I started because all I ever saw was people covering the Boa intro song and thought it was lame how there were many more great songs being completely overlooked. I'm also in love with the Welcome to the NHK OST just like I am with Lain, so you can find a whole bunch of NHK songs I did as well as a few more Lain songs on my account.
Thats pretty good stuff. Im a bass player myself and have tried to play the theme of lain bass lines, which I love. However I cannot for the life of me learn songs by ear. Which I made a post about in the music forum recently.