Blind Guy,
How blind are you?
There is a device called a fillinator. It is a syringe designed to plug a carto in the end of. You dip the carto in juice and pull the plunger to suck juice into the carto. This could free you from the flavor limitations and extra cost of prefilled cartos.
It was specifically designed for the blind.
Also, how do you read this forum? Do you have someone surfing through it for you? Or are you using speech software?
It might be a good idea for everyone to stop the blathering on over who makes the best tank system. It's creating a lot of clutter for Blind Guy to have to sort through.