Answer: Ilex aquifolium variegata is available in several Oregon nurseries, but I cannot find any in Washington State. Perhaps it's worth a trip to Portland? If so, contact River Rock Nursery in Clackamas at 503-658-4047.
I'd start with a small shrub, 2-3 years of age, for ease of training into a topiary. While larger specimens can be trained, you'd need to cut off the lower branches, which will leave knobs and scars. If you start with a seedling or small shrub, you can rub out the buds as they develop along the main trunk and there will be only barely visible scars.
Find a small plant with a single main stem and remove all but the topmost leaves. Rub out any leaf buds along the trunk just as they begin to swell. This will force growth at the top.
Best wishes with your topiary!
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