I've built a 'trial' aquaduct on DF, to see if it worked. You build one fortress which is your starting point, build the pumps etc. Abandon, then build another fortress right next to it, and continue the aquaduct from where it was.
For example: If your aquaduct finished at say, (60,10) you start your continuing aquaduct at (0,10)
Now, water will not pour accross into the new aquaduct you just made, however once that is built : (repeat until you have aquaduct from A to B)
You go into adventurer mode, hit the levers you will have, pump the water in, the water will flow from fortress A to B to C to ... Destination.
When you reclaim on a fortress that you have done this, the water you have pumped there / lava / giant kangaroos / adventerers dead corpse is all there.
So you could create a magmaduct and have magma forges along the way if you wanted to say, cast it out of iron.
Only limiting factor in this is X pumps (put as many as you like here, it makes no difference) can not pump enough water so you will end up with it drying out, to solve this, make 'repeater stations'
Basically this will involve creating a cystern in the sky (or wherever, the aquaduct must be above ground) and pumping water from that along, so the process is:
River -> Pumping Station -> Repeater -> Repeater -> Destination -> Kings bedroom.
Lather Rince Repeat, as needed.