Good suggestion
No. Maybe I could make sth useful to you in a program though. What I use with some melee AA builds:
[combo holds]
combo1=RButton:LButton
which makes LMB be held if you hold RMB. The advantage over what you have is that this can be either configured on toggle (Tab for example) for shopping / inventory management or made to activate with a delay so that nothing happens if you briefly Right Click instead of holding it for a defined fraction of a second.