The only resort
DVC is agressively selling is Saratoga Springs. However, you probably can buy points at BCV if that's what you want as DVC does reclaim some contracts via their Right of First Refusal whenever a transfer occurs. If you call them and say "BCV is the only resort I will consider buying", I suspect they will find a way to accommodate you.
However, the downside to buying BCV through Disney is that you're going to pay a premium price.
To buy BCV through a the resale market, you'll probably pay around $75 per point, plus another $2-5 per point for maintenenance and closing costs. That will get you between 37-39 years' worth of points, depending on the banked/borrowed status of the contract.
By contrast, to buy BCV through DVC you'll pay a flat $89 per point with no additional fees. That should get you 37-38 years' worth of points depending on the Use Year you choose.
It's actually a better deal to buy SSR direct from DVC. Right now they are running a promotion whereby you can get points at SSR for as little as $85 each (with no closing or other fees), and you get 49 total years of ownership.
So, if you want BCV, the cheapest alternative is to go resale. If you need to buy through Disney (because you need the financing or don't want to deal with the hassle of a resale), just be aware that you're leaving a lot on the table ($$$ and years) by choosing BCV over SSR.
Good Luck!