Arthur, I've received communication that you're seeking multiple, large, established plants of Los Angeles for your employer, an architect? The intention is to use them to recreate a period garden for a job your company is doing? Is this correct?

Unfortunately, you are going to fail. This can't be done. There is NO source for older roses like this of any real size. What you found in your shopping is pretty much all there IS to find. No large, commercial sources produce these older roses as there is no mass market for them. The "majors" produce the standards of the recent past which are well known by name, and their own new introductions they can charge higher prices to cover their royalty costs. The "secondary producers", the ones which supply Home Depot, Lowe's, etc., produce roses going back usually up to Queen Elizabeth (1955), but more often, much more recent introductions, and those, again, are roses which have reputations associated with their names and are easy for them to produce. A cultivar requiring more effort due to its inherent difficulty of propagation, such as Los Angeles, won't be produced by anyone but the smaller, specialty growers who will take the time to preserve them. The ONLY sources for Los Angeles, and 99.9% of older roses are going to be those already mentioned and none of them are going to produce them in very large quantities as it is extremely rare anyone wants more than one at a time. Because all of them deal primarily by mail, the plants are most often only liner to one gallon size. For something requiring dozens of a particular old rose, and especially if they are required in larger sizes, you would need to contract grow them well in advance of the planting need.

If this is specified by an architect, if you can, do yourselves a favor and educate him that procuring quantities of large, established specimen of older roses is no longer possible in the vast majority of instances. There simply is no market for them, making it impossible for anyone to have such things on hand when requested. He, or you, are going to have to change the specs for the job to use whatever you can find in the size and quantities you require, and that is NOT going to be a 1940 Hybrid Tea.

You also would have saved yourself, and your employer, five weeks of searching (from your initial post on 10/21) had you stated you required 30, established specimen of Los Angeles. We could have all told you they don't exist, choose something else. Good luck.