Can anyone point me to a source for 10mm to 12mm long high current beryllium copper springs?
Here's one but it's quite a bit shorter than what you're looking for, unless you pull it out:
http://www.mtnelectronics.com/index.php?route=product/product&path=25_81&product_id=385
Otherwise ebay.com has a lot of them depending on the specific dimensions you need :) Though sometimes it's hard to know if the springs are real BeCu or not from Ebay.
Mtnelectronics was the first place I looked. I found a seller with springs that might work. No dimensions listed but seller replied to inquiry with dimensions of height 13mm base diameter 12mm top diameter 7.5mm.
ebay link here
What about these? http://kaidomain.com/p/S026605.DIY-Bronze-Spring-Battery-Driver-Contact-Support-Springs-7_6mm-x-10mm-5-pcs
Thanks finges. Ordered a few myself. 
@finges Just saw the post. I ordered the springs I posted the link to but will order a few sets of those bronze springs too. Thanks.