That'll work just fine, though many find the limited sweep angle of typical flat bars to be unnatural for the wrists. Good ergonomic grips help tremendously (Ergon offers many good options).
To be honest, you can get a very good aero "tuck" on any handlebar. On flat bars, simply place the hands closer to the stem, bend down, and tuck your elbows in. Note that this is similar to the "most aero" position that a road cyclist can get (more aero than when in the drops) - watch videos of pros descending mountains and you'll see what I mean. For longer rides, the position when on the outer bar-ends is similar to riding on the hoods of a conventional drop bar (depending on the width you cut your flat bar).
Some handlebar options to consider, since you're considering alternatives:
Flat bar alternatives with more sweep/similar options for aero positioning: There are MANY alternatives, depending on your own preferences and physiology. Some samples:
http://www.somafab.com/archives/product/condorina-bar
http://www.profile-design.com/titec/...rs-/h-bar.html
http://www.jonesbikes.com/h-bar.html
http://surlybikes.com/parts/open_bar (can be installed upside down to give a shallow drop instead of a rise)
An alternative to the typical "drop" bar is the "dirt" drop bar:
less forward reach, shallower drop, flared drops.
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http://salsacycles.com/components/moto_ace_woodchipper/
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http://www.on-one.co.uk/i/q/HBOOMI/o...idge_handlebar
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http://www.somafab.com/archives/product/junebug-bar