Hi nickerbokker, I can tell you that finding an ethical blue dane breeder will be a challenge, there are a lot of BYBs that breed blues.
From my experience, you don't find a lot of blue danes because they are difficult to produce. They can inherit problems such as color dilution alopecia
http://www.upei.ca/~cidd/Diseases/dermatology/colour%20dilution%20alopecia.htm , but you can drastically reduce your chances of this disorder by finding an ethical breeder.
First, I would start with the Great Dane Club referrals. This won't
guarantee an ethical breeder, but you can eliminate the majority of BYBs that way.
Second, know what questions to ask. Any breeder that acts offended or tries to make you feel ridiculous for trying to do your homework is a waste of time, move on to another. Here are some helpful links:
The first is sorting through breeders and weird websites:
http://www.angelfire.com/anime/gdrsw/sortbreeders.htmlThe second is a 'Buyer Beware', if you scroll down you get a list of 'Do's and Don't's':
http://www.angelfire.com/anime/gdrsw/buyerbeware.htmlThe last two are websites containing information on suspended breeders. The first is an out of date list on Dane breeders(although some of the suspensions are still in-force):
http://www.angelfire.com/anime/gdrsw/greatdanewatchdog.htmlAnd this one is the AKC suspension index, all breeds, by breeder last name.
http://www.barkbytes.com/suspend/suspindx.htmThis is also a good resource for finding a good breeder:
http://www.danemist.com/ABCs/Good luck with the search, if you have any questions or need help please feel free to contact me any time!