I have a stallion like that. He has a few lines to Nazeer through Aswan, and lots and lots of Crabbet breeding. He's 1/2 Spanish (the YM in Spain used a lot of Crabbet imports for their foundation). His sire is the spanish, and is by SS ORion and out of Pascion S (both can be seen on the Stanley Ranch website). They are super athletic Dressage and Jumping horses, but Orion has also produced endurance horses.
Lady, Mat's dam, was a Kasio daughter (2 x Aswan, 3 x Priboj) daughter, out of a Perlezon daughter. Lots of endurance, racing, and cow horses on that side too. RD Arizon, a son of Perlezon, was especially noted for his endurance foals, and was a 1/2 brother to Mat's gdam. She also has two crosses to Witez II (many race, endurance and cow horses), and Kellygar (raffles bred.. many relateds are on the endurance trail).
Mat is only 3, so not doing endurance yet. He's getting Dressage groundwork done now (he was a late foal.. turned 3 last week), and then will do reining for a few years before we do Endurance. He is built for it though, and has a lot of relatives doing quite well. He will produce it, as the spanish and russian horses are very "homozygous" for certain traits, including stamina and athleticism, as are his crabbet lines. I will be getting some pics soon that I'll post.
Currently, he's only available by approval.. meaning, I have to know about the mare, but I am open about what he is bred to. I think he will cross well with the English/Crabbet lines, as well as the Egyptian crosses. I would hesitate to bring him to a Straight Spanish mare, because they really should be bred to straight stallions, but a spanish bred mare would work well too.