Ah, thank you, that's certainly good news as I've heard some countries don't allow that.
PR is 10 years but holders of LT residency (should I truly be eligible) require only 5. I'm too lazy to pull up the link that told me so, and it seems that it's not too important if it's incorrect as long as I behave myself.
My grandmother lives here in Australia, but as by item 4 here:
http://www.sakura-iloe.com/shikaku/longTermResident2.html (unless it's outdated or false) she's still considered Japanese for the purposes of the visa even if she's no longer a citizen.
You are quite correct regarding the sponsor, but it is possible (not certain) that either my grandmother's brother or her nephews and nieces could help me seeing as I've visited them a few times and I'd only ask with a decent bit of money in the bank.
Thanks for pointing out the POSSIBLE flaws in my assumption, you were right in doing so as I could have been caught in a sticky situation.