I have bought 100mg strength stuff from Xtreme Vaping. Good quality/price and no problems with ordering/shipping. I use it to spike my 36mg juice to boost it up to 47mg strength. I like it strong....
Careful messing with the 100mg liquid. I don't think it is as dangerous as some people make it out to be....but you do need to be a bit more careful.
I use Vapor4life for all my flavored juices, cartos and batteries.