Live Pen (personalized, but not persistent)

Hi

I'd like to be able to create a persistent Linux live pen, then use the first session to personalize it (change keyboard layout to portuguese, install Keepass2, VLC, some Firefox plugins, etc) and then somehow either stop it being persistent or make an ISO from the pen and create another pen from the ISO (non persistent this time).

Is this possible? The aim is to have a very secure live pen for online banking, but I can't just have a non persistent pen because then on each session I'd have to start from scratch (install keypass2, change keyboard layout, etc).

Thanks