Hey King, yes - I would think the Elipsas could go down into the 40s depending on your room. People like the Bryston sub crossover, I know, but some have also mentioned it (and other crossovers) altering the flavor of the sound from their speakers, in your case the Elipsas.
I also know that JL is coming out with a crossever in the (near) future, and rumor has it that it will be a little cheaper than the Bryston.