Out of sheer boredom I was thinking of airlines that have similar fleets. One pair I came up with was UA and BA. They share:
Longhaul: 747, 777 and 767
Shorthaul: A319, A320, 737, 767 and 757
Obviously not in ratio, BA have a higher proportion of 747s in longhaul, and United a higher percentage of 767s. And the 757s are a bit out of skew too! Other than that the ony difference is UA's lack of A321s and that they operate a handful of 777 domestic flights.