Here's the Nexus 4 production number from 
Nexus 4 Owners Estimate One Million Handsets Have Shipped Since November 2012 Launch | TechCrunch
	
	
		
		
			October 2012: 70,000
November 2012: 90,000
Dec 2012: 210,000
January 2012: 550,000+
		
		
	 
Unsurprisingly, it was a disaster in demand/supply management.  
Google/LG have learned their lesson.  They will have a lot for sales in the first week.
 
30,000 Nexus 5 carrier units reportedly resting in LG Canada warehouses
30,000 Nexus 5 carrier units reportedly resting in LG Canada warehouses
		
		
	
	
This is just the
 carrier unit for Canada.
Countries that carried Nexus 4 on GooglePlay:  USA, Japan, Germany, UK, France, Spain, Italy, Australia, Canada.
USA, Japan, Germany, UK, France population combined is 651 million. 
For just these 5 countries, 30,000 carrier units / 34 mil =
 737,000 carrier units / 651 million 
Add in Italy, Australia, Spain.....
CONCLUSION:  The first week supply will be 10 times greater for Nexus 5 compare to Nexus 4.