I aim for the same but if I am in a hurry I'll live with anything between just past the inside of the dropout to almost flush with the outside of the dropout. Basically the rule(s) are: don't ever hit the QR lever assembly or the QR locknut. As long as that never happens, everything else works. Too short is a PIA to get the wheel located right but does work just fine. The QR and locknut do all the work. The axle is doing nothing. (Now this may not be true of inferior QRs or QRs with non-steel skewers. Wouldn't know. I've always just used decent asymmetrical steel skewered QRs.)

Ben