If you haven't already done so, check out
JustStrings , lots of 6 string sets from a bunch of manufacturers. I know in my area it's almost impossible to find 6 string sets of any type in the shops .....
I personally really like the LaBella flats, but you might want to look at some TI's if you prefer a little less tension. D'Addario, Dean Markley, SIT and many others have 6 string sets in flats, rounds, chrome, whatever ...
