There is so much at stake, so much money, so much national pride and reputation and many careers, not just the cyclists careers but everyone around them, that everything is kept very secretive. One thing is for sure, these guys will do anything they can if they think they will get around the tests. Even the doping experts aren't sure what these guys are doing exactly.
I think there are a lot of different products they combine hoping it will add upp in the end, many new experimental peptides etc. Then they have the Therapeutic Use Exemptions put to use, which means you can use certain asthma medications, hormones like T3 and cortisones and so on.
None of these are as effective as EPO for example but like I said they are hoping everything combined will add up. These guys are even inspected for track marks so it's not easy to dope, even use of saline drips is problematic.
Cyclists are at the forefront of new doping techniques.