Since they don't play the same frequency range there is no reason to "match" speakers and subs. Also, the companies that make great speakers rarely make great subs. On the other hand, companies that started with subs usually go on to make some very good speakers.
It's a toss up for me between the sealed and vented. With my DIY sub, I went sealed so I didn't have to worry about adding a subsonic filter. With these subs you don't have that worry since they have taken care of that in the design. Can you live with the larger, vented cabinet?
Power Sound was founded by Tom Vodhanel. The V in SVS. His partner in Power Sound is another SVS alumnus. If you look at the 15" driver that is assembled in the US, I'll bet it comes from Fi Car Audio. Scott's company was one of two suppliers to the early days of SVS before they took their...
http://www.powersoundaudio.com/ is another option. Most of the time I would suggest SVS but with a room of that size, a 15" driver is required. If you are handy with tools, you can really go crazy with a DIY sub. $700 would get dual 15's or a single 18".