Except that it would take significant mods to bi-amp the L-1090's as they come with just a single pair of terminals. Better to spend the money on a good pair of speaker cables and a high current amp.
01-21-12: Ricplaya
...They (L-1090's) are a completely different animal then the L570s, there is no reason to run anything else with the 1090s. I can't imagine if they were bi-amped how good they would sound!
Also, since the columns are so narrow, it would be good to get a set of outriggers from Soundocity. I bought a pair of ADS's own optional wide-stance bases for the speakers, but that was in 1988 and I lived near their factory. They'd be very hard to find now. The wider stance was helpful so the outriggers should be even better.