Keep in mind the size of the pump will also effect the needed basin size. If you can picture a 500 GPH pump there would be a trickle of water in the stream. With 5000 gph there would be a lot more water in the stream.
There is the option to build several pondless streams instead of one. The result can look exactly the same, but each reservoir can be much smaller. You'd need one pump per reservoir, which means running electric, but you can switch to using low head pumps which are cheaper than the high head plumps to run. Also, if (when) you have a leak it's easier to track down. You can also use different size pumps on each section to get different effects.
There is the option to build several pondless streams instead of one. The result can look exactly the same, but each reservoir can be much smaller. You'd need one pump per reservoir, which means running electric, but you can switch to using low head pumps which are cheaper than the high head plumps to run. Also, if (when) you have a leak it's easier to track down. You can also use different size pumps on each section to get different effects.