Vintage Gardens: http://www.vintagegardens.com/
There are others as well, but this is where I buy my roses. I also purchase roses occasionally from Roses Unlimited. There are many own root antique rose vendors out there. Did you search on Google? When I perform a search using 'Antique Roses' as parameters, I come up with many of the own root antique rose nurseries including the above and Antique Rose Emporium, Ashdown Roses, Countryside, Heirloom and Rogue Valley. Good luck!

Thanks for the suggestions!

Appalachian Roses

Most of the warm climate boutique nurseries don't bother growing a lot of once-bloomers, particularly cold climate ones. And at this point, they are very few cold climate boutique nurseries.

Rogue Valley seems to have the best selection though I have not ordered from them before. High Country Roses carries once blooming antiques on their own roots. They are good people to do business with too.

Here is a link that might be useful: High Country Roses

rosefire.com

Check out whoever you want to buy from on Garden Watchdog.

Here is a link that might be useful: Garden Watchdog

If you go to HelpMeFind's website (http://www.helpmefind.com/rose/index.php) and type in the name of the rose you are looking for, there is a tab where it says "Buy From" and it will give a listing of nurseries selling that particular rose. Many of them (like the ones jbfoodie mentioned) sell their roses as own-roots. Hope this helps.

Here is a link that might be useful: Help Me Find

I find the people at Rogue Valley very acommodating and helpful.

Carla

I can personally give high recommendation to Vintage Gardens, High Country Roses, Ashdown, and Amity Roses. Heirloom used to carry a lot of OGRs but they have cut way back on that. I haven't personally ordered from Rogue Valley but I consistently hear good things about that nursery. Appalachian is new on my radar but they have the advantage is that being closer to you, shipping should be less.