[QUOTE=mvp;8645042]
I went and watched some in-hand stuff at an Arabian Sport Horse show this past weekend. It was interesting to see the crosses and, especially, the variation in those.
IMO, buying the Half-Arabian means having to consider the individual horse carefully. I think the F1 cross— bringing together two breeds each selected for different traits-- can be a crap shoot. I wonder if you experienced breeders agree: There’s not a great way to predict how these unrelated parental lines will blend?[/QUOTE]
NOT a breeder of Half-Arabs. However, I have bred a few nice purebreds and in researching good matches, I was repeatedly told by very successful breeders) that you get the best results when you breed like to like.
In other words, you don’t breed looking for different traits, but to reinforce the best ones and potentially improve weaker areas. So you’d look for a stallion that has many of the strengths your mare has. And offers the potential to improve her in other areas. You may end up with an exact replica of your mare, but if you wouldn’t be happy with that, then you shouldn’t be breeding her. 
If you extrapolate this to half Arabs, you’d be looking at crossing with a hot blood – TB or saddlebred or a warmblood with Arab or TB blood in the background. You’re looking for mates that match more or less. I’d also look for pretty good size on the Arab side, to minimize the possibility of getting a 14.0 cross.
Personally, I would stay away from Arab draft crosses or Arab QH (unless it’s Appendix) crosses. I just haven’t seen very many I liked.
That said, unless you’re going to breed the horse or you’re buying a weanling, it’s pretty much the same as with any other horse – what you see is what you get.
PS – the star of the MSU program appears to Ensignia, who was bred by Bishop Lane Farms which is in Northern Califonia. They stood Monogramm (I bred to him twice) at stud for years, and know a thing or two about sporthorses. You might contact them.