Now, if this has been brought up before, I apologize, but as far as I know, it hasn't yet.
Just as the name suggests, I got the idea in my head that it should be possible to use RP2's Diamond Saw (or its equivalents) to create reinforced stone slabs, panels, covers, and so on. With Eloraam's addition of frames, and the ability thus to create massive doors/elevators/whatever suits your fancy, R-stone slabs would allow for blast doors, ordnance elevators, and probably a whole lot more than I can come up with.
There is one point I'd like to make, though - if the stone does gain the ability to be cut, it might be a smart idea to also decrease the blast resistance for each smaller piece, if possible. The reason behind this is because if the blast resist stayed the same at all thicknesses, people could just place 8 covers back-to-back and create a nearly-impenetrable wall of R-stone just one layer thick. For SSP, this wouldn't be a huge issue (the worst you'd have to worry about is multiple creepers), but in SMP, it would make PvP horribly unbalanced, as even nukes would be rendered virtually useless.
So, with that said, what do you guys think?