Here is a great skirt for little girls that I found over at The Long Thread.  It is reversible, and you could make it with different fabric on the inside.  If they spill anything on one side – whip in inside out and voila! – they have a clean skirt for the rest of the day!  You can buy the pattern over at their Etsy store; it downloads as a PDF pattern with all the instructions.  Sizes range from 4 through 6 yrs and it costs only NZ$12.  

Now if only they had a reversible pants pattern for boys, I would sure find them handy for those hot chocolates at the cafe.