At least more left than right:
1. Reverse side of selector keyhole.
2. Mount selector lever on opposite side of bar.
3. Build new receiver cover.
4. Put cocking handle on left side.
I'm guessing you'd need to either work with a pre-bent blank or a flat with dimples but reversed holes.
This would still eject to the right, but as a left shooter, that's what I deal with already.