So I finally got around to taking a stab at a variation of this brilliant idea:
Instead of tomato puree I bought a jar or random tomato sauce from Tesco and puree'd it to make it eliminate chunks and make a smooth coating for the meatballs, which were also bought pre-made and ready to cook from Tesco.
After spending 30 minutes in MC trying to decide if I needed a sequesterant, I said "fuck it" and decided to see what happened without it.
Low-acyl gellan at 0.2% of the marinara puree blended in to disperse, then heated to a boil to hydrate.
Meatballs sous vide @ 55C then deep fried to sear. Put on stick and dip into sauce to coat evenly, allow 30 seconds to gel, then repeat dip about 3 more times.I grated some cheese over them as an after though, next time I will make a pile of microplaned cheese and dip the balls in right after the final coat as its gelling.
I was worried I'd have to try a bunch of different gellan concentrations, but I guess I liked out with my initial wag. Sets and holds without any dripping or peeling off the meatball, but only just barely noticeable as a gel as you bite into it.
I pretty cool idea all in all. I'm probably going to do a few more tests and variations before breaking into MC@H and using the pressure-cooked marinara for a final version. I suppose I'll have to come up with a meatball recipe as well.

Edit: Here's round two, with a more planned application of cheese. The sloppy one looks that way because I tried putting a last coat of sauce gel over the cheese, just to see what happens.
They are pretty cool little appetizers.