First off most of the Dwarf Crosses are dwarfs bred to normals and the offspring back to normals. So they aren't 50% dwarf. This is what I've been told by reliable sources that I trust. Normal dwarf crosses can reach 14-16ft with no problem. Infact go through the pages and you'll find a dwarf tiger cross that imo isn't dwarf. You had mentioned dwarf yellow head in your post above. These are NOT dwarfs. I had a 10 1/2ft male Bali yellow head now if a male can reach 10 1/2ft think about the females. I'd also like to add that he was very underfed and should of been a few feet longer when I recieved him. I know of a 16ft pair of bali retics and have heard of 20fters. Bali is heavily populated and therefore large retics are usually caught and skinned. This is another reason why many of these very large constrictors are unhead of in nature. Snappy nature? Retics get this rep from all of the w.c. imports that come in, much like blood pythons. Both of these can calm with with a bit of handling. Under 10ft looking into true super dwarf retics as well as kayaudi dwarf retics. NERD'S Jampea female is now approaching or maybe has reached 15ft now. There has also been talk about Kayaudi and Jampea retics being the same animal under two different names. From what I see Kayaudi's seem to max at around 9ft. I'm currently looking into the Golden Retics or "Selayer" Retics. Known to be a smaller Local (These aren't dwarf just a smaller local much like the bali yellow heads). Animals I've seen have been beautifully market! Again when all these "dwarfs or smaller locals" came in off the boat gravid at 6ft or less were c.b., their sizes seemed to keep growing. C.B.B. Dwarfs or smaller locals have proven to be much larger then their w.c. counterparts. Bob Clark is always good, Shawn, Cutting Edge Herps has Kayaudi's...There are a number of good guys to deal with. "Usually" when dealing with high end herps you don't have the scam artist to deal with at least in my experience. If they can provide pics of the snakes coupulating, eggs, as well as hatching then you should be fine. Anyways Sorry for rambling on.
John