I have quilted for others even before the days of my longarm...and I can tell you, LA customers can whine just as good as any others you may meet! You will need at least 400 hours on your LA before you can be considered good enough to quilt for others, at least according to some of my LA friends. And believe me, that 400 hours comes hard.
So...if you want to quit your daytime job, start practicing RIGHT NOW and you should see some great progress in 400 hours or so! And need I add, "Good Luck"!!