It depends on where in Aus you are, but there is a guy in Melbourne called Bruce Linsdell who runs BLS suspension and is awsome at rebuilding shocks that arnt meant to be rebuilt and custom modification work like what you are reffering too. He has done some custom work for me in the past and has worked for both Ohlins and Honda Aus racing team so his suspension knowledge is awsome. The only problem is that he is always flat out so you may have to wait a while to get anything done.