Neat idea, Seahorse! Please tell us how it works out!
One of my customers gave me a neat idea that he swears works but since I haven't tried it can't tell you for sure one way or the other... Buy any old cheap powerfilter, bigger the better, take out all the filter media cartridges so you're left with an empty box, fill it with macroalgae, put a clip on light, plug everything in, and voila! A crude insta-fuge! I'd say you could probably seed that with some pods and they'd continue to grow.