Take a look through the OldMiniBikes photo section, there are a lot of bigger mini bikes to be had it all depends on your area as to what was sold. Time to figure out what type of riding you want to do on or off road the requirements will demand different machines.
Craigslist or ebay is where most people find a suitable ride. Remember it is suppose to be fun so being a bit over-sized for your ride is part of having a mini bike.
Good luck and use this forum to define your search. Steve