That dual SVS sealed 12" set is a good deal. I have a friend who matches that sub with his Magnepan 1.7's. Another possibility, and spot-on with your budget, is a pair of these sealed 10" subs by Emotiva.
A recent issue of Home Theater did a comparo of a Paradigm SuperCube (about $1K), an $1800 REL, and the awesome JL Fathom F212. The Fathom was the best. At $1800 the REL offered up a steeply-sloped spike centered on about 44 Hz, and the ported Paradigm had a more usable, fairly flat, broad response curve held up by a couple of damped resonant peaks. What caught my eye, however, was a separate review of an Emotiva 5.1 set of speakers, and the $499 XRef 10 had a reasonably flat, easy to blend curve more like the JL (but not with the JL's dynamic power). I suspect a pair of those would work well with what you want to do. I gotta say, however, that for $150 more I'd probably try the SVS pair first.
A recent issue of Home Theater did a comparo of a Paradigm SuperCube (about $1K), an $1800 REL, and the awesome JL Fathom F212. The Fathom was the best. At $1800 the REL offered up a steeply-sloped spike centered on about 44 Hz, and the ported Paradigm had a more usable, fairly flat, broad response curve held up by a couple of damped resonant peaks. What caught my eye, however, was a separate review of an Emotiva 5.1 set of speakers, and the $499 XRef 10 had a reasonably flat, easy to blend curve more like the JL (but not with the JL's dynamic power). I suspect a pair of those would work well with what you want to do. I gotta say, however, that for $150 more I'd probably try the SVS pair first.