Here's a handy thread, a firsthand chat about what the Lensrentals guy paid for new sensors installed in 5DII & D700:
Don't scratch your D800E sensor - FM Forums
RCicala
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Registered: Jan 09, 2005
Total Posts: 1980
Country: United States
City/State: Memphis TN
p.1 #5 · Don't scratch your D800E sensor
"I haven't had the pleasure with a 5DIII yet, but 5DIIs were $480; 7D's around $400. D700's were about $550, but the last one we had was over $600. D7000's are just under $500 now, they used to be just over $400."
The Nikon D7000 aps-c sensor costs more to replace than Canon's 5D Mark II sensor.