First of all, even though I give Melbourne so much shit, especially that Melbourne Model, I'll agree that it's a decent university, so is Monash, they're both equally good and both have their good points and their bad points.
I would honestly say that if you end up at Monash and regret for the next few years that you aren't at Melbourne - go to Melbourne. As crazy, unrealistic and vague as you sound in regards to why you prefer Melbourne, I sympathise with you because I know how it feels to be doing something that was never really your first choice. It's like doing something just because you can, whilst your dreams lie elsewhere, and I know how crap it feels when your friends tell you that they're at Melbourne, because deep down, you wish you were there too.
Some things aren't easy to put into words and I understand that this is one of those things, if you want to go to Melbourne and you feel a passion for it, you should go to Melbourne by all means. If there's something that I've learnt over the past year or so, it's that you should never settle for second best if you've still got a shot for what you really love, cause even though you might regret it later, you'll never forget that at the time, it was what you truly wanted.