Hmm. I think that many of the larger MSP430 chips (the ones that aren't programmable by spy-bi-wire) include a serial bootloader in ROM. For instance, the MSP430F149 (which is pretty old) datasheet says:
The MSP430 bootstrap loader (BSL) enables users to program the flash memory or RAM using a UART serial interface. Access to the MSP430 memory via the BSL is protected by user-defined password. For complete description of the features of the BSL and its implementation, see the Application report Features of the MSP430 Bootstrap Loader, Literature Number SLAA089.
I'm not sure that it would be a good idea to count on the LaunchPad being available as a $5 programmer. It's certainly not "breaking even" at that price, and could be discontinued pretty much any time... (OTOH, LaunchPad is pretty ripe for a cost-reduction spin, using a 430 with native USB instead of a separate USB chip, and etc.)
The days of parallel port programmers were also the days that "real" development tools cost $249 for the "low cost" version. That said, I think I'm a lot happier when the programming protocols are "open" enough that you could implement a simple programmer given some pins that can be wiggled. That includes AVR's SPI ISP protocol but not their JTAG, for instance. I haven't looked at where TI sits...