Firefighter, have you considered using a full-sized LaScala and cutting off the top end to move it 'elsewhere'? As long as you keep the mid/high components in a near on-axis with the woofer you won't suffer from the plan other than destroying a cabinet. "Butt ugly" LaScalas are out there for the fixer upper for around $500 or so and you would have two to tear up.
As far as your plan to go ahead and build the 8-10" versions, look at the center channel signal frequencies reproduced as a guide for what you want to at that spot. If your heart is set on this plan, the lack of bass capability is perhaps acceptable for a speaker in this location; but no other one. In the end, you being happy with what you got is all that really matters, right? The rest of us will continue to just blow the dough!
