although you say your LFS doesnt stock some of the desired species it is highly likely that they can still get them from their supplier and only dont stock them as they arent easily sold, after talking to them they may order them in for you, equally there are many places online to buy your fish, i havent brought online however so i will let other members give ideas of recommended sites :)

and i highly recommend looking at harlequins, they are a great schooling fish :)