Hi John,
You do get some wierd ideas, trying to beat the manufacturers way of doing things.
I fully understand where you are coming from with this, I raised this point with my machine supplier and was told, 'that is just the way it is'.
I did a load of accurate measuring, and came to the conclusion that what I would be gaining in spindle movement, to me, it just wasn't worth the hassle, I will just move the tailstock a little closer to the chuck when required.
It looks like you are determined to go for it, so, as long as you don't try modifying the machine itself to get you where you want to be, I would say try it, but be careful. If you get an MT stuck 'up the spout', don't try to belt it out and free it off from the nose, a couple of bad side knocks will introduce deformation that equates to years of wear, but wind the spindle fully out to remove it, and come in from the back with a drift.
While you are at the tailstock end, maybe you should consider this dead easy mod.
http://madmodder.net/index.php?topic=424.0Bogs