I wonder if any "more affordable" tube or SS monoblocks may drive the big Thiel nicely.Have you considered the Odyssey products? Their monos sounded very nice to me (driving other speakers). Carver mentioned above is another choice. Both are SS, neither is very expensive...
A friend of mine had the 3.6 and we tried a number of amps of all sorts on them (Mark Lev, Krell, you name it). The best sound we got, which was a completely different sound, was with a pair of Symphonic Line shiny mono blocks. It was an unusual sound, very ethereal, lots of high frequency detail and great coherence and, unusually for such a small-medium speaker, very good presentation of a fully blown orchestra. It was surprisingly dynamic as well! Good speaker indeed. (OK, it is actually limited at frequency extremes, but it is not annoying.)