http://www.cree.com/products/ledlamps_hb5round.asp

would these be good to make some led back up lights?

 

Your looking at the chips which are not 12,000 lumens, to get 12k lumens from led you need to look at vision-x or rigid industries and pay nearly a grand..

Look up the rigid industries dually or dually D2's for backup lights, amazing light output for a good price

 

12,000 lumens is insane.

Not cheap either:

http://www.rigidindustries.com/product-p/eseries30.htm

This is the data sheet for what you posted, traffic LED's:

http://www.cree.com/products/pdf/LED...-030(1213).pdf

 

I have 66 cree LEDs for reverse.

 

yea nobody needs 12k lumens for reverse amyway :p, one hid is roughly 3000 lumens

you can buy a pair of the regular rigid duallys for $180 and thats plenty bright