Why not have a small bait well with aerator on board out of the water(or in) and the eye of the curious? This does not mean the well has to be on the tube just closed off to the visual attraction and motion of live bait in a well.
Yes there would be a drag problem I'm sure. Drag shmag if your catching your target fish its a trade off.
Why couldn't the well be hydro dynamic to alleviate some of the drag if it becomes an issue?
Why does the bait well have to be utilizing the surrounding water for sustaining the bait?
Why does the well have to allow the bait to be seen by predators?
I say it doesn't.
Please don't tell me the seals will smell the accumulation of bait near your tube. We all goop enough fish sauce on our plastics to attract every seal and predatory fish out there so be real.
Ed's bucket on a boogie board is the best idea I've seen so far.
How about another device? Anyone?