I do believe Adire will have a temporary backorder on many items because of problems or somethin with supply, not sure though. If ya would have made this post about a month back you could have got mine for $110 shipped //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
In that case, another option is the Dayton Titanic MkIII. It's a little over $200, shipped, which is cheaper than an RE SE15. An Ascendant Audio Atlas 15 would likely be around the same price.
If these are both too far from your budget, a used Tempest is likely the only decent alternative.
...actually, you could try contacting Mr. Marv about a 15" Oz Audio Matrix Elite. I seem to remember that he could get one to me for ~$180. I'm not sure if he's still able to do this (they weren't in stock when I spoke to him a while ago), but it might be worth asking.