Came across this whilst looking for rules for 5&3 dominoes.
The rules appear exactly the same as normal cribbage, it is just played with a pack of dominoes instead of cards.

I think it would be an interesting variant. Maybe with double 6, 9 & 12s as options.
http://www.domino-play.com/Games/DominoCribbage.htm

The question remains, is it a cribbage or domino variant?

A crib flush must be 5 cards

I've played nearly 2000 games of Cribbage on here, I must have had it at least once. The odds are about 1 in 1000 when looking at the maths. Allowing for multiple cribs per game, statistically I'd expect about 4 in my time here.
I suspect the real odds are actually lower because some players won't put two of the same suit in to the opponent's crib.

got a flush in your crib? just wondering ...thanx