NHWR wrote: “In any given week, where in the US can I go to see at least 30 warmblood mares between the ages of 4 and 7 with training appropriate to their age over 16.1 hds?”
This sort of question really frosts me. It takes very little effort to find 30 such mares. It took me exactly 15 minutes on the internet to come up with 30 such prospects in the Mid-Atlantic Region (the largest Hanoverian breeding area outside Germany), all within 3 hours of BWI Airport outside DC/Balt. For example, there are 8 listed on the Mid-Atlantic Hanoverian Breeders website, 3 on the High Point Hanoverians website, 2 on the Rolling Stone website, 5 on the Some Day Soon website, 1 on the Bae Prid website, 2 on the Goodness Ridge website, 1 on the Crosiadore website, 2 on the Kent Island Sporthorses website, 2 on the Hilltop website, 2 on the Autum Hill website, 1 on the Windswept website and 1 on the AHS website sales page.
I stopped looking after I got beyond 30. But I am CERTAIN that (as Mo Swanson from Rolling Stone farm and others already have said) many of the other breeders listed on the Mid-Atlantic Hanoverian Breeders website – http://www.mahanoverians.com/index.html have or know of mares that might be suitable. And, I only looked at Hanoverian links. There are LOTS of Oldenburg, Dutch, Holsteiner, and other warmblood breeders in this region.
I strongly suspect that California, NewEngland, the Southeast and perhaps other regions of the US would offer similarly good horse shopping opportunities.
Undertake the “bother” to spend a few moments checking out the wonderful mares that are available here in the US, many of which can be easily found just by using the internet!