Hi
For all of you who don't mind using the stylus, i might have a solution.
Install easy debian from the "extras"-repo.
Then start LXDE, activate the package manager and install claws-mail from there. This way, you have a stable version and all plugins available, which allowa you to store your mails on the device.
Before you download your mails for the first time, don't forget to disable the option to automatically delete the mails on the server, which is automatically activated in claws.
the window with your mails listed is big enough to read, but to read a specific mail, you have to mark it with the stylus until the rightmousebutton-menu pops up and then select "open in new window".
The only thing i have to figure out now is how to place a direct link to claws in the maemo-menu

Cheers!