A micro sample is basically a small piece of a block. You start off by crafting a glass tube from glass and cork. Then you combine that with a block in the crafting table, this gives you a micro sample.
A container would also be craft-able. This would be able to hold about 4 or something samples. Also it would occupy one inventory slot.The turtle could then use these samples for comparison. Each sample could be used about a couple of hundred times. Based on the sampled material or the material the container it was made from.
turtle.compareToSample("slot","sample number")
I think this would be a cool addition, while preserving the "fourth wall". Give me your opinions.
Onto number two, Laser tagger.
A laser tagger gun/hand-device. And this in combination with an electronic backpack capable of holding a floppy drive. Or a rednet transmitting backpack. You shoot the gun on a block and it will store the coordinates on the floppy-drive or transmit them over rednet.
English is not my native language. xD