I think Falcon is gorgeous. I definitely like the short stocky/draft look of the vanners, and I'm even saddened by the more sporty look that Friesians seem to be plagued with lately. Then again, I like my horses on the stocky side...no matter the breed!
I think you have thought this out pretty well. Sounds like you will be able to provide for the foal whether you can sell it or not and that's the important thing. Truth be told, I doubt you'll trouble selling a vanner. They often sell before they hit the ground here...and even then they are selling for 10K+. Some of them have ATROCIOUS confirmation and yet they are still selling.
The problem with people against the breeding of horses is many of them don't believe in horse slaughter either. Getting rid of legal horse slaughter really messed up our market here in the states. There was a day (not too long ago either!) that scrawny, sickly, old horses would go through auction and get bought up by local slaughter houses. Now those horses either spend extensive amounts of time in a cramped trailer on their way to canada or mexico OR they end up getting shifted from home to home for the rest of their lives. As sad as it is to us humans, many times death is the more humane option. Too many times I've seen people buy up the poor looking lame horses that would have gone to slaughter five or six years ago just to realize they don't have the money to care for it's issues properly. Some of those horses will run through the auction house two or three times in consecutive weeks before the owner settles on a low price and sells to the meat buyer. It's really, really sad.
However, not everyone is into rescuing non-descript horses so there will always be a market (although sometimes small!) for well bred horses. My friends who breed show dogs NEVER have trouble selling their puppies and often have waiting lists. There is a huge difference between them and some backyard breeder though. They know what they are breeding for and they have done their research. They often put in more money then gain. Despite the number of dogs in shelters, there will always be people out there looking for their well-bred pure breeds.