Try a few on. I find that modern suits are all pretty elastic and the measurements the manufacterers present are not necessarily upper limits. Some also do tall versions, so xxxl-t may be a possiblity. Conversely, Radiator used in Fremantle used to do custom wetsuits, but I am not sure if they still do.
To aurimas mystic wetsuits have a huge range of sizes with a great chart to determine your size I've just picked up a set for the family and the quality is superb,I especially like the velcro ancles you get in and out of your suit super quick,and as the are made in Europe I find they are warmer , ipicked up a 5/3 star awsome wettie
If you google wetsuits melbourne you will get a few results. Otherwise most surf stores stock them. You may want to call around as some places will do custom made wetsuits then you can get one that is unique to your height etc.
