I also have a pack like the one KN6KB linked to, and it works great and is easier to use, but isn't really the best for building into a radio because of the power switch and unnecessary bulk, and you can't really cut out the power cable and replace with your own (like Power poles) unless you want to do a bit of surgery.
It works great as an external pack though!
For the Turning pack, I forgot to mention: you could always buy a ready-made balance charger if you want as well, but the buck converter and external balancer is more versatile for me.? It works great with solar panels, you can plug it into any wall wart of high enough voltage, or you could charge from your car battery on the go.
