I believe a 29 could be developed into a very nice reef....the same as any other size display. Folks over in the nano forum keep sweet lil reefs in displays much smaller than 29 gal.
The process is much the same no matter the size....smaller allows for a greater potential for fluctuations in water chemistry....more water volume is easier to keep stable....but small or large either can be successful.
...and I also would like to welcome you to the forums and please do keep us posted as you progress. Don't hesitate to ask questions along the way...folks here will gladly help all they can.