[slyv]

The problem is that it is doable to create an encrypted email client, but the problem is how does one then send this off encrypted to a gmail account? There's no practical solution to handle that unless you want everyone to be on the same server, which then makes email pointless since there would be better solutions. But, unless google and the other big players adopt encryption, there's really no real way to do it streamlined.

I would, however, recommend adopting PGP, as that seems the simplest route to go.