These come up on Ebay UK from dealers - why not just buy a couple from there - postage is not that expensive & USA Import Duty is only 4.5% as far as I know - usually at some pretty good prices - will still work out much cheaper than buying a new full 5 speaker set up.
There is a guy on AVForums UK (of which I also belong) who is selling 3 x SibXL & 2 x Sibs - you might want to ask if he is willing to ship to you in the USA - I think you might get a good deal:
They also come up regularly on Ebay UK & good deals can be had so don't rush for just is available at the moment if they are priced too high!
If you are looking to recoup some costs I am looking for a base and pivot that I lost for a focal sib speaker. If you are willing to sell a base and pivot I would really appreciate it. I placed an ad in the personals but I doubt that will pan out.
Here is a link to my ad.
Who AM I
Speakers > MB Quart VS05, Boston VS260, Snell K7
Subwoofer > Mordaunt Short Aviano 7
Receiver > Tascam PAR-200, Pioneer VSX-30