We have several 3.5-10x40 Leupolds on hand, most VX-3's but also at least one VX-III. The eye relief on all of them doesn't vary more than about half an inch, which is usually about what ER varies on scopes advertising constant eye relief.

But the easiest and cheapest way to buy a constant eye relief Leupold is buy a fixed-power.

“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck