[flybouy]

If you have a ceiling light that's say 6' away you may still be able to tap into it. One way to "cheat" a wire over:
1. Turn off the light switch or remove the fuse. Remove the ceiling light and disconnect the wire to it.
2. Take a suitable length/gauge of wire ( It will have to be long enough to reach the vent and back to the entry hole for the light plus some) and a second wire about 1' long (this will be the new wire to connect to the light) and solder the 3 sets of wire together and shrink wrap it to the wire that was connected from the light. .
3. Push the wire into the hole to clear the splice and enough to make a loop (2-3")
4. Use a stiff wire or an electrician's fish tape thru the hatch opening (trim ring removed) above the ceiling and hook that wire. Pull it to the trim ring opening.
5. Cut the wire in the vent hole space, install fan and connect wire.
6. Pull the other end of the wire you cut at the vent back thru the hole for the light.
7. Take that 1' remaining wire and connect it to the light.
8. Push the excess wire up into the hole and secure the light.
9. Go have a beverage of your choice while enjoying the man made breeze.

I hope this is clear, if not I'll try to explain further.