I see mentions of a short version of Birkat Hamazon ("Birkat Hamazon Hakatzar"). R Yitzchak Abadi wrote one "based on the Rambam and other Rishonim", R Yosef Eliyahu Henkin is mentioned here as having one as well and there might be others.
I knew of an abbreviated Shmonei Esrei but not of an abbreviated Birkat Hamazon and would like to learn more:
- Did a common nusach emerge?
- What have been views of other poskim regarding these proposals?
- Are there communities where it is mainstream to recite these abbreviated birkat hamazon lechathila?
PS. This reminds me of a story I heard, maybe in the name of R Kotler, saying: "I don't understand why people say they don't have time for breakfast: 5 minutes to eat, 15 minutes for birkat hamazon and that's it!"