Though I've never seen a language that is completely free of whitespace restrictions

I have. But such languages invariably have much simpler syntax than Perl. In most cases they're oddball languages created for hack value that advertise Turing-equivalence as an important feature and have never been used (or intended) for anything serious.

As far as real languages, Perl5 has fewer and more reasonable whitespace restrictions than average I think. I do wish we had whitespace-folding multiline strings like in Inform (but not at the expense of regular strings). I believe Perl6 will allow such a syntax to be added to the grammar without having much impact on anything else (provided the syntax for it is carefully chosen to not conflict), which will be nifty. Some of the languages in the lisp family are pretty reasonable about their use of whitespace too. You do have to have whitespace between items in a list, but it makes no difference how much whitespace or what kind, and the restriction is unlikely to bother anyone since the whitespace is not redundant: it's the only syntactic element between items in a list. (Usually the syntactic feature that bothers people about these languages is the pervasive use of parentheses, especially if said people aren't accustomed to using an editor with paren-matching, auto-indentation, and sexp-based cursor navigation. Perl goes the other way and allows you to use a lot fewer parentheses than many other popular languages, and I think this is going to stay mostly the same in Perl6.)