Adamson's in Langley, British Columbia, lists four "Prairie" roses, which I believe are from Paul Olsen, and they appear to have other varieties from Canadian breeders.

Helpmefind lists only seven roses bred by Paul Olsen and only one, Prairie Snowdrift, is listed as commercially available. Adamson's Heritage Nursery, mentioned by Petaloid, does seem to be a good source of Canadian-bred roses but of their four Prairie roses (Prairie Celebration, Prairie Joy, Prairie Princess and Prairie Snowdrift) only Prairie Snowdrift is an Olsen rose - actually its a sport of Morden Blush.

Here is a link that might be useful: Adamson's Heritage Nursery, LTD

Did you notice the incredibly low whole sale prices? I wish I had a nursery here in Sweden so I could import a couple of hundreds of these roses cheaply. There is great demand for all Canadian roses in this country.

Hi. Paul is out of town until February 5, 2011. I am certain he will be very pleased to hear of your interest in his roses.
If you should go out to the Devonian Botanic Garden around June 19th, you'll be able to see his roses and 100 or so more spring blooming Canadian bred roses at their best.

Is the Prairie Snowdrift going to be available in California? I would really like to buy one or two. Unfortunately I either called or visited all the nurseries in my area and can't find anyone who knows anything about it.