My recollection is that RU sends gallons.
The only other vendor that I know of who regularly sends gallons is Chamblee's and I'd say their plants are about the same size.
If we're talking bands I've gotten large plants from Vintage and RVR this year and they were very well rooted large plants.
That said I'm not worried if they are small sometimes. By the end of the first Summer it's usually hard to tell which ones started out small.

Antique Rose Emporium I believe sends 2-gallons. Rogue Valley has some gallons and perhaps larger. They are close to you. When you get into the larger sized pots shipping costs can skyrocket.

A few years ago J&P sent fantastic own root roses not potted but wrapped like grafted bareroots. They were the biggest ownroots I have ever seen, and the shipping was reasonable. Unfortunately this is not the case any more. This year I got very mediocre own roots from them but, true, I ordered late. Still, it was a disappointment though they will resend one of the roses that was badly damaged.
ARE is excellent and they pack their roses superbly.

I am absolutely addicted to RU own-roots! in terms of non-bands. Here are examples of how huge and healthy my RU roses have been when I first placed them in their pot after they landed on my doorstep!

What's wonderful is that RU roses take off right away and become close to 5'6" for non-climbers in their first year. As for Climbers, they start climbing, LOL!

The photo is a bit deceiving (plants looks smaller than they really are, because the photo was taken at an angle pointing downward) but the tree rose in the background will give you an idea of the proportions in terms of height.

That's actually an interesting question. Most of the major vendors are slowly transitioning from grafted plants to own root, even for their bareroot offerings. I would venture to say that most bareroot floribundas that you can purchase now at any nursery are in fact "own root" varieties. With hybrid teas, the process is not so far along, so only the newer varieties of hybrid teas (which were selected for introduction in part because of their ability to grow vigorously on their own roots). The only list I have found as to which currently offered bareroots are actually "own root" varieties (as opposed to grafted on Dr. Huey) is on the website of S&W Greenhouses. S&W's bareroot season is over, but their list is still accurate, and it will tell you which varieties to look for at your own nurseries (or any other nursery that still has bareroots from the major wholesalers -- Star, J&P, Weeks). In short, if S&W had them as "own roots" then so does everyone else who is selling them from the same wholesalers. So go to the link and pick any of these varieties in the "own root" list from any major nursery, as long as it has one of the major wholesalers tags on it (Star, J&P, Weeks) and you will be getting the biggest "own roots" that are currently for sale. These will all generally be two year old field grown plants. Some nurseries have them as true bareroots (with no soil on them), but they also can be offered in "milk cartons" or peat pots or even something the nursery itself has potted up and still be the same stock that came in with the 2010 bareroot season.

And they will all be bigger than anything you can get from the Vintage, ARE, RVR or any of the vendors that grow their stock from cuttings -- those are generally all one year plants, or less, in the case of "bands." But do not get the "container grown" plants that J&P is now selling -- those will be one year old greenhouse-grown plants in square plastic containers and not as big as the "own root" bareroots.

The other option if you want really big own roots is to get them from RVR in what they call the 5 gallon size -- those will be two year old plants, generally. Shipping on that size is very costly though, so you are better off financially getting the bareroot "own root" varieties from your local nursery.

Here is a link that might be useful: Own root varieties in nurseries as bare roots for 2010 season

In my experience the biggest come from Antique Rose Emporium wit RU second in size..
Olgs

I'll be trying Roses Unlimited (RU) this season.