Meal Time Madness

So oftentimes I share tips, tricks, and successes with you all in hopes of sharing my knowledge.  But occasionally, I come to you asking...even begging...for some tip or trick one of you might have.  Today is one of those days!
Current stressor at our house?  Meal time...dinner most specifically.  Levi is an absolute terror throughout it, making it very difficult for us to eat, much less enjoy, or time together/the meal in front of us.  He has always been a bad eater...something we are used to from our days with Colton (who miraculously has moved on to eating pretty complete meals these days!).  But now instead of just not eating, Levi has decided dinner time is his play time.  He spits, he throws, he feeds Chipper...and he cracks up about it.  And Colton cracks up about it (which obviously really doesn't help matters).  Meanwhile, Josh and I spend the entire "meal" issuing threats, begging him to eat, and eventually questioning why we even try to eat a meal together!
I've done a bit of research attempting to find a magic fix, and unfortunately it seems we're already pretty much doing what is suggested.
 We've been sitting down at the table to eat dinner together from the time Levi was born, so the routine should be well established.

  I don't believe in catering the boys meals to "kid" foods...they eat what we eat...but I do try to cater our meals to things that are more likely to be winners in Levi's book (although he also totally surprises us sometimes with things that he enjoys, so we keep up variety too!).
We have withheld afternoon snacks in hopes that he'll be hungry enough for dinner.
We don't allow him to have a treat (or sticker, or screen time...we've tried every reward possible) after dinner if he doesn't eat his dinner, and have even resorted to setting a timer, so it's not an all-night proposition. The only problem with this approach is that usually by the time we get to the timer/threats at treat, we are so completely frustrated...and eventually he does finish, so he ends up with the treat even though we are at our wit's end!
We've tried staying calm when he's doing something he knows he's not supposed to.
We've tried getting angry when he's doing something he knows he's not supposed to.
Basically, I feel like we've tried everything and it's just a matter of somehow, someway getting it through his thick skull that meal time is not his show time.  But how?
Seriously, folks, any and all suggestions are welcome!