Minecarts with programmable redstone output

There should be two additional rails for minecarts: one for writing the redstone power level and one for reading the redstone power level stored on the minecart. This would allow, for example, a redstone output strength of 2 to be written onto a minecart as soon as it passes over the programming rail, and this stored redstone strength of 2 would then be output again when the minecart passes over the reading rail. This would enable countless possibilities for redstone mechanics. I think it fits perfectly into the vanilla Minecraft concept and would also make minecarts much more exciting again.