I wanted to do the same as you and get new motors and chassis, but it is difficult to be sure what will fit and expensive. If you are good with the cosmetic work I know it can be done. I have seen others do it with different locomotives but they had to modify the shell or chassis and they are true artists in my opinion. I am a mechanic not an artists.
I don't know of a book. The Tyco manual tells you to send them in for repair, but the repair station is long gone.
I know most say the motors are disposable but you can rebuild them. Its tedious, but with patience and lots of light you can do it. I suggest you work over a box to catch any runaway parts, especially the springs.
I restored my old Tyco ALCO Century 430s and 630's by buying more of the same, cheap in poor cosmetic condition, but good running locomotives then I used them for parts. Sometimes it takes 2 or 3 to make one good one. Occasionally you will get lucky and only need 1 good 1 for parts.
Also there is a seller on eBay selling brush kits for the Tyco motors
http://www.ebay.com/itm/160601414048?_trksid=p2055120.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Hear is the thread I started when I got started with my project/obsession
http://www.modelrailroadforums.com/forum/showthread.php?32073-Tyco-244-Alco-430-Restoration
Be careful, with me it became an obsession and I have 18 of them and 11 in great running condition. I ran one under one of my Christmas trees last Christmas. Three of them did not need to be restored, but I spent nearly $325 doing it. I have 2 more on order and don't ask me why because I can't give you a logical answer. They are just special to me. Christmas is another obsession for me along with Lionel.
I wish you well with your project.