$150 seems a bit steep to me Tony - especially when I have a steel drum in the garage wating for my OTS Maxi Smoker project. I bet I could use a piece of that to make my own mangal grill........
Yeah, not cheap for what it is. But hey ho. Over here we pay double for our Weber products.
With a little skill and the right tools, I don't think it would be difficult to make one of these. You could design it as such that the insert sat on the tabs that hold the grill, and extend it's height accordingly. All you would need is to buy the long flat skewers, (shashlik style).