The topic of Litium batteries have been touched several times, but do you have an idea what to buy?  

Depends on what you want to do.  Do you want a Lithium battery of the same size and CCA, or do you want a smaller battery so that you can move it to a different location?

Yeps, sorry for posting at wrong side first... BUT back to topic.

I have BCB kit installed and need some mods for winter time. Have to do something otherwise darkness will definatelly kill the mood. So I ordered Raptor, opened carb....
Finally decided to try to install smaller battery in modified Airbox and replace that with a Cone filter.
So trying to Find battery to this space.... or modify batterybox to smaller size and use airbox for other purpose (tools and martini)  
Antigraphity and others are upto 200usd (inc shipping), chinese LI-PO 150USD, Small acid/gel versions 100 usd....
And if any European brothers (or sisters) are reading this, please also post if any good sources in EU.

I did the mini-battery mod 6 months ago.  I used an absorbed glass mat battery with 6AH and 130 CCA.  This is the one:  http://www.batteriesplus.com/product_search/33984-Xtreme-Permaseal-High-Perfo... It's the Batteries Plus equivalent to the same one Boule'tard used in his mod.  So long as you don't leave the lights on for a long time, it works great - plenty of cranking power.  You could probably put it anywhere you want it; I mounted mine on my swingarm shelf.  I didn't even have to lengthen any wires!  

I looked at the Ballstic batteries - however they recommend that you use one of their chargers periodically tp "balance" the cells and extend the life of the battery.

I have decided to order one of these batteries - as they are built with the balancing system built into the battery.  For the $ 40 extra I am goiing to use the 12AH battery instead of the 6AH - they are both in the small A size cse.
 http://earthxmotorsports.com/products-page/cbr1000/etx12a/

One of the things that I wonder about mounting the battery under the swingarm and behind the engine case - is the heat.  The battery I am looking to buy has an upper operating temperaure of 60C (140f).  Looking back at a previous thread Verslagen measured the case temperature at the oil filter cover at 170-195 degrees.  That information makes me want to put it up near the stock location where it will be out of the heat.....and out of the spray from the rear tire.

My Double RYCA Build buddy is using the 8-cell version.  No problems.

I've been running my mini battery since last July.  Never had any issues, even idling in the Texas heat.

The bracket on the swingarm is used on the CA models for the charcoal canister in the evac system.  If the temp is safe for that, I would assume it's pretty safe for a battery, two.  Just my $0.02