A quick note on sigils: recently I have been thinking that the dollar sign sigil could be used to denote place forms such that $_ is the top place form. Any place form could be cast into a function to be used on any object, for example you could use the place form $first on a collection like &$first(coll) and you could always set the value of a place with something like setf($first, 1).
Inside any function $_ will refer to the argument of the function, so you could program without ever using named parameters like in Perl 5. A parameters list like ($x,$y,$z) will just create new place forms rather then variables. I think this would make for a pretty interesting programming language semantics. On the other hand, I don't see much use for the @ and % sigils because I just consider lists to be structures with numeric places and maps to be structures with general places, so I actually prefer PHP style sigils.