The most powerful SET amp I know of is the WAVAC HE-833, which is a 100 watt monoblock. That's almost twice the power of the Cary. At least one person is using this beast to drive his Sound Labs, which means the amp is quite capable of driving a very difficult load. The price is in the same ballpark as the Cary. Replacement 833 monster output tubes are quite reasonable - around $250 each last time I checked.
Here is the address of WAVAC's HE-833 page: http://www.wavac-audio.gr.jp/he833_e.html
Here is the address of WAVAC's HE-833 page: http://www.wavac-audio.gr.jp/he833_e.html