Good idea(s), ElTee... yet, I'll post my results right now
Here are some full-res samples of the upscaled MI2-artwork (the JPEG-compression blurred the texture a little bit):
I don't know how it looks when printed (as mentioned, at this scale the artwork would make a poster of 45 x 60 cm - which is about 17.7 x 23.6 inch), but I think the faked detail might work really good on this one. The logo might need some touch up, and the "by RON GILBERT"-line is still in there, so this is not yet ready.
I've tried the same technique on the MI1-artwork:
It might work as well (although the artwork isn't as detailed as the one Steve did for MI2), but the image itself still needs some touch-up work.
And last but not least, I've played with the "Sam & Max"-cover, although faking detail with a texture didn't work too well with the comic style, so I only used the brush-stroke effect on these:
Really not sure about this one... I guess there's still room for improvement.