The tendency to pronounce “el” as “al” has been heard before in places like New Zealand and Norfolk Island. Linguists call this the /el/-/æl/ sound change, and from a physiological point of view it’s not such a strange occurrence — when the tongue moves to form an “l” sound this encourages a change to the vowel that precedes it. But this is far from the whole story.According to a commenter, this makes the pun in TISM's album title Machiavelli and the Four Seasons rather more obvious ("Machia Valli"), but if that's the case the Melbournian /el/-/æl/ swap has been around since at least 1995.
There’s a related but contrary process called /el/-/æl/ transposition. This is when people say words like “alcohol” and “alpine” as if the first syllable was “el”.
Technical paper (in pdf form) here.
(Do Melbournians still say "Travelling!" when in a hurry to somewhere? Or have they wisely stopped?)