The Berkeley Botanic garden had Puya raimondii for sale in 1 gal. pots at the 2010 spring sale. I assume they have more.
They have bloomed, after about 25 to 30 years, at both Berkeley and San Francisco Strybing gardens. They survive 30” of rain in our winters (December to April) and get regular/supplemental watering year round. Both locations are under heavy marine influence, think foggy San Francisco. 80F would be unusual for a summer day, and 35F would be an uncommon winter minimum.
Berkeley has two 7’ plants near their rose garden, north of their other Puya beds. The last plant to bloom in Strybing, 2008, was so massive it fell over during the wet winter.
Puyas: bromeliad beauty queens - SFGate