I also make all my own packs. Lately I have been buying 2500 mah Nic Metal AA Energizer cells at Walmart (4 for $8.99) and have made numerous packs with them. I use an 800 degree F soldering tip and have been very happy with them as TX and RX packs.
I made a jig that holds the cells in place and I use CA glue to attach the cells to each other. Battery tabs for making the electical connections can be purchased from most of the battery suppliers (Batteries USA etc...)