Here is a list that I have compiled. I have tried many of them but not all. There are many more I am sure but these have been around awhile and have quality selections. Many are reference quality Masters.
These should get you started.
Good Luck!. . . . . ENJOY!
AIX Records
http://aixrecords.com/
Archive.org has a lot of high res downloads of various live shows. Lots of high resolution available - including Hungry Lucy! and Calexico! Check it out!
http://www.archive.org/details/audio
http://avaxhome.ws/hraphile
bandcamp.com
Blue Coast Records
http://bluecoastrecords.com/
Bowers and Wilkins - Society of Sound
http://www.bowers-wilkins.com/Society_of_Sound/Society_of_Sound/Music
Cantaloupe Music
http://www.cantaloupemusic.com/
Chesky Records
http://chesky.com/
eClassical.com -- based in Sweden
Gimell Records (96k/24bit, 48k/24bit, 44.1k/16bit of the The Tallis Scholars)
http://www.gimell.com/
HDTracks
https://www.hdtracks.com/
High Res Music
http://hiresmusic.com/homepage.html
High Definition Tape Transfers
http://highdeftapetransfers.com/storefront.php
High-res download test bench (free samples only)
http://www.2l.no/hires/
iTrax
http://www.itrax.com/
Linn Records
http://www.linnrecords.com/index.aspx
NAIM Audio
http://www.naimlabel.com/
NIN.com for those who like Nine Inch Nails
Qobuz
http://www.qobuz.com/
Reference Recordings
http://referencerecordings.com/
Rhino
http://www.rhino.com/