No. I started bmus perf this year. I only know of one guy who is combining bmusperf with law, and that was with specisl consideration from the dean/ he got top marks/ was head boy etc etc.
Do you want a career in music anyway?
Been there done that- I had a chat to USyd around 2 years ago when I wanted to do something BMus/ Sci -ish, your best bet is doing just science, or science/ arts, and picking lots of arts-music subjects.
And you can't combine BMus perf.
The jazz unit at sydney con is extremely competitive and you need to be gun at improvisation and such... anyway, it'll help if you check out the sites for the conservatories you want to study at :)