Actually there is a circuit which is analogous to a capacitor using two comparators, some redstone dust, and some opaque blocks, but even they don't work exactly like real capacitors. I guess the closest analogous circuit I could think of to a resistor would be a comparator set for subtraction mode with another comparator feeding into it's side reading a set value from a chest. That way it can subtract a set value from an analog input. Obviously still not quite the same or really all that similar even, but I think it is about as close as you can get. You can even use an item frame instead of the chest to make it a variable resister, though I think you would actually need two if you wanted the full range of resistances (0-15), and you would need to subtract one from each before inputting them because item frames don't have a 0 output with comparators.
Of course this might not be terribly useful to you since it still won't work quite the same as a resistor in the real world.