Sprite rippers rejoice!
Except we already have the means to rip sprites without waiting forever for the next version of DOSBox.
In fact, I think the Windows version of Lemmings actually comes with a bitmap that has all the relevant sprites used for playing a level (namely, all the Lemmings animation).
What would be useful though is the ability to record solutions. This is assuming it will not degrade performance too much (depends on your machine I guess).