I have a set of the 12v Motorcycle Keis heated inner gloves.Had them about 5 years now.Still going strong.
Are these the ones you mean,
http://www.getgeared.co.uk/keis_heat...ping_feed_gg17
They were expensive and now even more so but they have lasted well.I think I paid around 40 quid for them but of course they have gone up over time.
Anyhoo,
You could rig up some connectors and power them from one of these,
http://www.ebay.co.uk/itm/12V-2800mA...AAAOSwo4pYGVWf
I don't know previous poster says there's a problem with LiPO.Please explain.
Note:I work in the Aircraft industry and there are billions of Lithium/Polymer batteries in use all around the world that give no problems including in everyday devices we use.