Anything special to consider when running a 12v "Bus" throughout my house?
A few things come to mind:


You need to protect the bus from overcurrent.  Even if your power supply has its own built-in protection, I would use an additional fuse (or circuit breaker) at the output of the power supply.  This way you can be sure the maximum current won't get away from you.  This leads to:
You'll need to use beefy wire.  In the USA, 15A circuits are wired with #14AWG, minimum.  If you want to use thinner wire, you'll have to fuse each leg appropriately.
If you do use #14AWG wire (or your local equivalent), don't use the typical cable used for household AC!  Although it would work out technically, it would cause major confusion and ambiguity.  You don't want anyone expecting 12VDC and getting Mains voltage (now or in the future).
At 12V, the current draw can quickly add up.  Keep this in mind as you add devices.  You may want to swap in a 24VDC power supply in the future.  It is a common industrial standard, gives you twice the power over the same wires, and still falls into the "low-voltage" category.


Adding to Point #4: If you choose local 5V converters that accept a range of input voltages (including 12V and 24V, of course), then you won't have to change anything if you bump up the supply voltage.