Single Roll, Double Duty

Is there any way as yet to either use the same die roll result more than once, or perhaps copy the result to use in a macro? For instance, in Torg a d20 is rolled and the value on the die roll is used for both the attack and damage values. Likewise in Hackmaster when a mage casts a spell he needs to roll a d20 to figure out spell mishap, but that same die roll is used to determine the difficulty for enemy saving throws. Is there a way to use the same value multiple times?

Nope. The macro system is strictly one-roll, one-shot. With your Mentor status, however, you can make use of the API instead, which can assign variables and retain rolls. The only other way to do it would be for multiple rolls and user-input to allow the end-user to manually enter was the previous result was via Roll Query's ?{RollQueryText|0}

you could create a macro like this that you manually input the old roll. /r 1d20 + ?{OldRoll?|0}[OldRoll] This is just a stripped down version of one of my macros and im not sure if it will apply to what you are doing.

In theory, I believe Roll Templates in the Update of Holding will allow you to reuse the same roll several times. Someone in the mentor forum that's been messing around with them might be able to give you a better idea of the capabilities.