I think that neither X10, Chapel nor Fortress had much impact, although X10 and Fortress share a lot of the same ideas with Scala, which successfully managed to build a community and ecosystem around it.
Just look at http://x10-lang.org/documentation/code-examples/small-examples.html?id=107 for instance:
def
for methods, val
for values, var
for variables, this
for constructors, no special syntax for arrays, ident: Type
instead of Type ident
, uppercase types, ... (and that's just the syntax).
It's pretty much the same for Fortress, but their site seems to be not working anymore, so I can't link to code examples.
My conclusion is that those languages' design converged and a winner emerged.