I just picked up a SureFire SC1 from Steve @ [url=www.adcofirearms.com]ADCO[/url].
It holds 6 batteries and a spare lamp (p60, p61) very securely - no rattles. Made tough and waterproof, it comes with an adjustable lanyard.
$14 from Steve. $2 per battery. He has the nice $4.00 flat shipping rate too (no matter what you order).
Anyone else try these out?