Lots of nice warmbloods in NSW. Regardez Moi seems to produce a nice type [Rubenstein bloodlines]. Another of the Ryans' stallions, Jive Magic [by Jazz], is very studdy but what I've seen of his foals have been nice, that being said I haven't seen much and it does depend A LOT on what the mare is like. I like Fiji R a lot, sweet stallion and very quiet, but haven't seen him in action. There are a LOT of imported bloodlines in NSW and some of the stallions that larger-scale breeders there have imported are from among the best bloodlines in the world.
However if you want a dressage horse a purebred warmblood is probably your best bet rather than using a TB mare. I like the wb/tb crosses for eventing more than for dressage. I haven't met one yet that had quite enough movement to be competitive in the upper levels of pure dressage. The TB has, IME, a tendency to flatten them out a little bit.
There's also a HUGE range in quality in the Thoroughbred breed and a TB with good lines for racing is not necessarily going to be any good as a dressage broodmare. My filly is apparently reasonably well-bred, but that's for racing. Different discipline altogether!
Breeding is a crapshoot, why not look at buying a weanling? That way you get the gender and colour you want and you're not risking ending up with something with wonky legs. Or a stillbirth. I'm not sure which would be more heartbreaking given that breeding to a good warmblood stallion for a dressage horse will cost a LOT of money and wonky legs do not a dressage horse make!