Is it possible to construct a category $\mathcal{C}$ with $\mathrm{Ob}\,\mathcal{C}=\mathbb{R}$ and for every diagram of the from $$a_0\leftarrow a_1\leftarrow\cdots a_n\leftarrow\cdots$$ the inverse limit exists if and only if the corresponding sequence $(a_n)$ converges and in this case the limits coincide?
One should probably give some restrictions so that there are enough morphisms. To throw away stupid examples like $\mathrm{Mor}(x,y)=\varnothing$ for $x\neq y$ and $\mathrm{Mor}(x,x)=\{\mathrm{Id}_x\}$ let's assume that for every $x,y$ at least one of the sets $\mathrm{Mor}(x,y)$ and $\mathrm{Mor}(x,y)$ is nonempty(maybe someone will suggest more adequate restrictions)
Probably this question doesn't make any sense, though taking category structure from the structure of ordered set makes $\varprojlim a_i=\sup a_i$ which is close to the desired.
Any results for other metric spaces are also interesting.