http://www.motoarenagc.com.au/welcome/page1.php
is the Triumph dealer on the GC. I run RAT rides on the first sunday of every month and RATBAGS have a ride on the last sunday, so you might be able to come on one of those. Alternatively, a group of us go out most Thursdays for a ride in the Hinterland but the pace is fairly 'brisk' and probably not suitable for cruisers.
http://www.scootntoot.com.au/
Are the most reputable and will hire you a Triumph America or a Ducati Monster 620, depending on what sort of riding you want to do, or these guys...
http://www.mopedcity.com.au/welcome/page1.php
Have some GSR 600`s, Z750`s and some dangerous looking chinese built Pagsta choppers.
If HD is your thing, these blokes...
http://www.morganandwacker.com.au/rentals.aspx
will hire you a Hardley Worthitson but they ain`t cheap!
Surfers Paradise also has half a dozen other motorcycle rental firms that will be cheaper than the the above but the fleets usually consist of tired looking Virago 750`s or Cagiva Raptors which have been flogged half to death and dropped more times than Britney Spear`s panties.
send me an email if you want to come on a Thursday thrash.