Brunswick. BBC and Tru Balance.
I have 6 and no, they are not for sale.
Best bet is to keep checking EBay as they show up there. Got an oak 1 piece for 99 cents.
Just be faithful and they will show up.
Another option is to check Bell Forest Products. The sell Mark Bear's
full splice blanks. They may be double pointed as Mark is a premier FS blank maker.
http://www.bellforestproducts.com/spliced-blanks/
It appears that Mark does make a double point and for $100, I doubt you will get a cheaper and better blank.