A saw some of these guys at big box today, marked A. sisalana from Altman's. I'm still not convinced. They do look sisalana-like, but also seem different. Besides, Altman's gets all their Agave labels wrong, why would they get this one right? :-)
there are two forms of Agave sisalana variegated... a 'floppy-leaved' form, and a stiff-leaved form. The former is also a dwarf plant. I am not 100% sure it is ONLY A sisalana, but it sure seems to be MOSTLY A sisalana.
Here is my Agave sisalana variegated next to an imposter Agave franzosinii (on the right), followed by a few shots of the 'other' Agave sisalana I have in another part of the yard. Sadly this second plant is planted in an area full of snails and it is being literally eaten alive