I was thinking about doing LEDs too when I was setting up my tank but after doing some research like you did I found out that a 29 is just too deep for most LEDs. Although you will have to eventually replace t5 bulbs they last almost two years so it is not too bad and they aren't very expensive.
Looks like our research has both uncovered similar info leading to the same conclusion.
How'd you hang your dual t5 fixture? Do you have any pics of your setup? Curious how it looks and how it lights up the tank.