Hey Jolly Green
Those tows like you pictured are possible (The Heated canine concept)..
Yet no stbility under water. They`re designed to be towed by a power boat at planing speed. Using body weight can make these tows turn slightly to ride the wake off the tow craft, yet kids tire of them quickly. They also have very little stowage space and due to their mass will slow you down in a big way.
Here`s a bit of fun....and yes with the right .`pilot and a careful skipper`, you can get some serious air time, (of course if you own a powerboat designed for wake boarders):
http://www.youtube.com/watch?v=hoBEtBkZ ... re=related (..to heck with towing, this looks like a blast (where the hell are their helmets)
Back to the basics, you might be better off with simple inflatable toy kayaks, yet if you`re carrying seriously costly gear, I suggest something inflatable made out of solid material (why not an inflatable dinghy)
They`re tough (have a $1k price tag, approx.) have a relatively flat bow that won`t damage your rudder unless you collide in heavy seas, and they can carry a 2 to 4 horse outboard if they are in the 5 to 6 foot range. They can certainly carry your goodies (including you and crew as a lifeboat......). I highly recommend if you go in that direction that you consider a dinghy with an Air Floor`to keep the weight as low as possible.
Due to their high freeboard that same towed dinghy can also be used as a tow vessel for your Island.
Consider also, if you have a TI, your crew can detach and you now have 2 highly capable vessels both being solo`d for one reason or another....like as a camera chase boat...
Regards
Fred