Well, I have not seen this, but how much is it? How many soffet vents do you have to paint?
I am sure that you will have over the course of your DIY projects a need for a spray paint mini rig. Why not invest $60 in that small Waggner Professional Power Sprayer. It would do the job very well and you could also use it for painting patio furniture, crafts and other small projects. It is adaptable for a pint can of paint to a hook up for 5 gallons.
I would not recommend using this for large projects as you will probably burn out the motor, but it is good for small things.
I really like mine. Keep it cleaned up and maintained and it will last forever.