The best thing someone could do for TrueCrypt security is to very publicly release a version with a backdoor, easily exploited, and difficult to detect, for anyone else to distribute. By making that a real threat, users will end up checking their source/compilation/results, protecting them against the same threat from real attackers.
That might be a cute object lesson in good security practice for the security cognoscenti, but the overwhelming majority of potential users in the world will just throw up their hands in despair and say that we can trust anything and privacy is impossible.
If we want ordinary people to benefit from TrueCrypt, a better idea would be to find secure ways of distributing signed and verified copies of the binary. I'm saying binary because most users in the world will be ordinary Windows and Mac users, not software developers. Most people in the world cannot compile from source.
Also, as a first step, we need to do this security audit of TrueCrypt.
(Not saying auditing truecrypt is bad; I'll probably donate some $ once I get back to the US)
This problem already exists, and is actually something Mac App Store, iOS/iTunes store, and Google Play do a pretty good job of solving; I assume there are some similar solutions for Windows (I don't really know the windows consumer software distribution space).
The extensions improvements in Chrome/Firefox (and I guess other browsers, but I don't follow them) also are a great step forward toward this.
Ubuntu/Debian do a pretty good job of locking down main repositories, too. It's really just a matter of training users that downloading random code from random URLs is risky.
Once locked-down distribution hits critical mass, you can probably get away with making it even more difficult and obvious-to-the-user-he-is-doing-something-risky in "sideloading" applications. You can also have corp/org security policies which prohibit this kind of thing.
Obviously there are sacrifices for this -- it becomes possible for a platform owner to restrict availability of apps based on non-security considerations, like being anti-porn (Apple), complying with the union of laws of all countries, etc. Or just outright commercial anti-competitiveness (again, mostly Apple...)
