[PLUG-TALK] Another use for 12 volt fans?

[John Jason Jordan]

I have a gas log fireplace that is sufficient to heat my entire house.
However, the fireplace is in an unfinished part of the house (soon to
be finished) where the vent duct is still exposed. This duct gets
pretty hot. In the remodeling/finishing about to take place I am going
to wrap and attach to the vent some wire mesh to facilitate better heat
transfer. But ultimately the vent will be enclosed, which means that I
need a vent at the bottom and another at the top of the enclosure for
air to circulate over the duct and mesh. My plan is to add ordinary
grilles at the top and bottom and computer-type fans to enable air
flow. 

This means that I need computer fans and a very small computer power
supply (for the 12v needed by the fans. Noise is a big factor here. 

1) I asked my friend Mr. Google about sound levels for computer fans
and came up with Noctua as offering the quietest fans. Does anyone have
experience with the Noctua fans or alternatives?

2) What about power supplies? I don't need a lot of current for my
plans. Are there very small power supplies (preferably without fans)
that would provide enough current for half a dozen four inch fans?

3) Does anyone think I am crazy?