In a direct conversion receiver, does the osc. run at
exactly the same frequency as the received signal?

Assuming the answer is yes;
Is it possible to have a high Q LC front end at the output from the
antenna,
split the signal and feed one output to the rf input of the mixer and feed
the other splitter output to an amplifier and use the amplified signal to
drive the osc input of the mixer?

Simple block diagram of proposed idea;
http://i395.photobucket.com/albums/p...conversion.jpg

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MikeK