I certainly did not mean to imply otherwise. Thank you for the picture. The plant looks ancient.
In the end it sounds like the greenhouse pix are going to be more helpful anyway in identifying the variegated agave at the start of the thread. Hopefully the overexposed plants here give you some idea of another extreme in appearance, or a frame of reference to compare other pictures on the web.
There is a useful conclusion here that's relevant to identification. Whatever the final size of an agave is reputed to be (and each plant does have a final flowering size), you can often expect to double or half that under different growing conditions, especially in container life. They are such malleable plants. Even in the sun there is a big difference in size between plants that get regular water, plants that get occasional water, and plants that get no water (beyond our annual 10 inches or less of rain). Or for example some people like to spoil their landscape agaves and that can lead to some outright monstrosities that have little relation to the plants found in nature. My preference is to protect them in pots until they reach landscape size, then leave them loose in the big bad world to fend for themselves. More or less.
