After going to places like Beijing, Shanghai and Hong Kong, i reckon the closest you get to good 'Xiao Long Bao' will be at Hutong in the city. It is just opposite Flowerdrum.
Be sure to ring them up and book a table before you go. Eating these xiao long bao is an 'art'. You have to pick them up carefully from those bamboo steamers, ensuring the gravy is still inside, dip it into some vinegar and devour it.
A good xiao long bao is one which has the best gravy and thin fine skin. Doubt any other places in Melbourne can be any better than Hutong in that aspect.
If you are talking about steamed or fried dumplings, the Shanghai Dumpling place at Tattersalls Lane in the City would be my pick. Another place worth mentioning will be 1+1 Dumpling noodles restaurant along Hopkins St in Footscray.
Btw, steamed dumplings and xiao long baos are 2 different things
My 2 cents