I don't think that there is an easy answer to your question. It also depends whether you mean you want absolute accuracy down to 0.1mm over a metre (that's .01%) or whether you want repeatability to within 0.1mm. Perhaps you want to transfer that measurement to something else within the 0.1mm.

Depending on the physical circumstances, 0.1mm repeatability doesn't seem too hard. I reckon I do that all the time in woodworking just with suitable stops and jigs, but the absolute accuracy is probably no better than 0.5mm 'cos that's what my eyes can see (and see next paragraph). And wood bends and stretches anyway.

Now to get absolute measurements right, that's another kettle of fish. It's going to depend on you having an accurate reference measure more than anything. You can go out and buy a 1000mm steel rule for under a tenner, but I bet you can't find a statement of how accurate it is. And then there are loads of other factors. Take thermal expansion as just an example. A 10 degree change in temperature results in roughly a 0.1mm change in length of a 1000mm steel rule. (Linear expansion coefficient of steel is about 11x10^-6). Now if you are measuring steel against steel then that's fine and they will change length roughly in line with each other, but if you are measuring aluminium then the expansion coefficient of aluminium is roughly twice that of steel, and so a 10 degree temperature change will break your accuracy requirement. (All that depends on which alloys of course).

But enough of that BS. It would seem possible to buy a 1000mm rule and then take the vernier scale off a small set of calipers and use that in the usual vernier method against the rule. It might work but it would need steady hand and eye.