One thing you should consider is that do you want to buy batteries cheap and have them last?
Packs nowadays are pretty cheap. A cheap set of matched 3300s can go for $30 bucks. Main thing is that you maintain them properly and you will get long life from the cells.
When in stick pack form, you really can't maintain the pack properly as the cells can discharge at different levels and are not equalized before charging. You can see premature pack failure from this. Also, the way they are assembled can cause the cells to get excessively hot and the connections between them aren't the best.
I know the feeling about how stick packs can be great, but for the cost, I would picking cells in side by side configuration and a good discharge tray. You will be happier in the long run.
If you still want stick packs, I think promatch sells some for good prices. Ebay is probably your best bet.
Also, Promatch can preassemble your packs for you and even install the connector you want too I believe? Soldering isn't hard, check out www.rccars.com
and in the motor forum look at what soldering iron they recommend.