I like that technique! I have done something similar at times, but very rarely because I only have my full-sized gas grill, and it's rarely worth the bother (plus it's impossible for several months of the year). But, after this post, I'm considering something like this:
https://www.walmart.com/ip/Expert-Grill-Tabletop-Gas-Grill/55041932
It's only $32 (USD) at Walmart, and it says it has a 12-burger capacity. The downside for the low cost is that it needs to be assembled, and people have said it takes a few hours. If not this, then maybe something similar.
They also have a charcoal grill for about the same price - with minimal assembly required: