I'm not sure what virtue work is. I've read some studies on bibliotherapy in prison settings (not sure if that relates for you).
I'm not sure what you are looking at studying. I just read, for a psych class, about Allport and intrinsic vs extrinsic religion. Maybe something like determining what traits allow a prisoner to benefit (whatever you are trying to determine) from positive psych and somehow looking at intrinsic and extrinsic reasons. Like, I want to study virtues or learn this psych stuff, so I can be a better person and eventually a good member of society and help others who find themselves in similiar situations, be a better parent... vs. I want to do this because the person teaching it is cute, I'm bored and it gives me something different to do, they may let me out of here early if I do this...
Sorry, I'm just throwing some stuff out there. I agree, it sounds interesting.