I plan on eventually having a pair of Angolan's.
They will continue to sell as they become more well known in captive breeding.
As pointed out they are uncommon in wild caught due to some nasty wars and the residual munitions.
If yours was the ad I am thinking of the snakes you listed in trade work out to a little bit higher than the current value of a pair of Angolan's (I personally have not seen even a proven pair go much better than $1500). So, that may account for the lack of interest.
The similarities with Ball's and the slightly larger size would make these snakes very popular if any morphs start turning up. That and their natural bead like scales.