Yeah, I actually got the normal Ripley the day I took that photo, and the Power Loader was just a few days before that, so those are straight out of the box. I like the paint job on the Power Loader Ripley pretty well, but the normal one could definitely use some attention.
You should definitely try it. I got my Frank Black figures for $25-$30 shipped, so they're not too expensive. You could probably get away with just removing the entire abdomen and then having the guts come out of the chest area, which would save you from having to dremel out the abdomen. That and cutting the figure in half are the hard parts, really.
I can't believe you don't have any aliens! As figures, they're way too fragile, but they look very impressive and you can't have a complete Aliens collection without an Alien. I would only have one, but I lucked out and got Chavez's alien with the broken leg for only $50 shipped. I was able to fix him up well enough to display, and I must say that having two does give me more flexible display options. You should also look into getting the power loader. It really does rock! In fact, I would put that before the Aliens, since I have a feeling the loader may be harder to find in the future.
To answer Badmoon's question above, I haven't broken any marines parts, but as I mentioned in the power loader thread, I did break a few things on the power loader trying to put it together. Nothing that I couldn't fix, though.