Hmm...just thinking out loud for a minute...
You could also drag a length of inexpensive interior-rated low voltage lighting (or doorbell) wire up to your remote point, splice on a plug, and use that for your DC supply. If you're pulling CAT5, it's not that much more effort (or that much bigger a hole) to bring some additional wire along for the ride. You could even run a second length of CAT5 along (you never know if you'll need a spare anyway), solder two sets of two
wires together, and use those for your DC.
You'll still need to pay attention and calculate for voltage drop with whatever gauge wire you end up using. But it may be an easier thing to do than having to muck about with a fancy PoE solution.
The only real advantage to PoE is that it uses a single
wire bundle. So it's neater and easier for the installers. (Especially if the data cable is already in place.) And also a bit cheaper since PoE uses a technically
"unassigned" set of wires you've already paid for.
That may be an important consideration when you're wiring up 20,000 square feet of office space in a city high-rise. But when you're only running a hundred or so feet of 'copper' in a standard residential wood frame building, the savings in wire really isn't all that much. So it's more a matter of convenience.
But again, if you're pulling a new
wire, dragging something along with it at the same time
doesn't add much work to the project.
Something to think about.