Gee - all the right questions...
Since the two motors have the same efficiency, if you were to travel at the same speed (say 20mph) one motor or two will use the same power and you will get the same range. If you have hills, then it may be that running two motors will actually use less power because the motors will be less loaded and will be running at a better point on the efficiency curve. The reality is, though, that you will probably use the available power and if you goose it a lot, the range will go down (so you may need more battery capacity).
Both motors get the same voltage and each requires a controller. At any given speed, each motor will only be doing half the work and so will use half the amps and generate half the heat as a single motor drive. But - when you pound it, both motors will run to max and you will draw twice the current as one motor - so your battery must be able to supply that. Ideally, you want a single battery that can supply all the current you need. This makes everything simpler to monitor and manage.
If you are going to do this, I would recommend getting a CA V3 with an external shunt to drive them so you can have a single throttle and single battery monitoring. It's also relatively easy to rig this so you can select to run on either one or two motors. I run on one at low speeds on bike paths to keep the noise down and get the single motor up into a decent efficiency range. Basically, you can rig this so it drives just like a normal bike - nothing unusual to control. Two motors will give you a top speed just a bit higher than a single motor, but not a heck of a lot.
Here's a thread about a 2WD MAC. He started with dual 8Ts and went to dual 6Ts. I don't remember anyone building up a dual 10T - that would be a torquey mama. See my build thread for some details on a another 2WD build using BMC motors - the equivalent of MAC 8Ts. These builds are similar in that they both use the idea of identical motors/wheels to simplify the control. Others are fans of mixed mode drive, but those solutions require too much management for me and are difficult to run at good efficiency since one motor or the other is always off the peak.
So - if you want to pursue this path you need to look at your battery current capacity for two motors, see if you can squeeze in another controller, and think through the controls you want and how to do them. This sin't complicated, but bad planning can lead to unpleasantness...
FWIW - the V3 will allow you to have 1WD/2WD PAS as well. This isn't too good for more technical stuff, but if you want to cruise groomed bike paths and have controlled assist for easy riding or health improvement, PAS works great. I also find it useful as a range extender since it keeps me honest with limited assist - I can't cheat by just twisting the throttle a little further. My PAS install is discussed in the build thread.
On the downside, if you are wailing away on more technical trails, 2WD may be a mixed blessing because of wheel spin and traction loss on the front wheel. If your speeds are low - not so much - but certainly a real consideration. This might be a real deal-breaker and push you to a bigger DD or perhaps one of
LightningRod's mid-drives.