built-in microwave vs. over-the-range
There are models of microwave ovens specificaly designed (ie. vent through the front) to be built in as an optional mothod of instalation. See the following link:
LINK > Built-in Microwave Ovens
Unless they're specifically designed for that type of installation, the best you could do would be to hang one under a counter (but not above a range).
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[This message has been edited by DanO (edited January 16, 2003).]