DOn't forget about the X10 XPT switches. Though they have one main set X10 address with the others being in sequence (e.g. switch set to A1 means firs switch is A1, second A2, etc...) the price is reasonable, and to control other H/U codes, all you need is a transitioning macro that triggers on one H/U code and activates whatever other H/U code you want. You can fit two of these in a 4x4 (dual gang) box. As far as price, you can get 3 of the XPT set ups (3 - XPT transmitters and 3 - 4 unit on off keypads) for less than one of the keypadlincs. Not to mention you have the option of getting other keypad configurations to fit the main transmitter giving you a little more flexibility.
While I do realize the extra flexibility of the keypadlinc switches may be worth the $$$ for some, but for those that are looking to go a little cheaper, the XPTs are great for their price. I have a few XPTs installed and I love them.