If this is just for the sake of not rolling 7 you can have a die with just odd numbers like 1, 3, 5, 7, 9, 11.
Having 2 of them guarantees an even sum.
Of course you would have gaps between the possible outcomes but not rolling a 7 is already a gap.
But it's not just for the sake of not rolling 7, it's about avoiding only that number to improve Catan. If you can't roll any odd number in the first few rounds, tiles with those number become way less valuable, which changes where you want to place your villages, which affects the entire game.
The 7s can be replaced with 0s to fill in some of the gaps and allow for odd number rolls.