But for how long, using very small resistors to limit the current through an LED is not the most reliable of techniques especially if you want it to work over any sort of temperature range.
Well that's the thing, who knows what the OP's intentions are? Reliability and temperature independence are concerns one develops with time and experience, and to me it sounds like the OP just wants to blink some lights and the only real concern is whether or not the circuit will start a fire
The simple circuit with resistors and transistors can be cooked up on a breadboard in minutes, while a constant-current driver will take quite a bit more effort.
Should the circuit he proposed prove to be too unreliable then for sure, the next step is a constant-current driver, or perhaps a common-collector configuration for the transistors.
The Quick Shield
: breakout all 28 pins to quick-connect terminals