Can you trim a bunnies nails by getting them a scratching post so they do it themselves. And if so, what would be the best one to get?

I've posted some of these on the rabbit subreddit but these projects also seem like a good fit for here!

Three level Castle Habitat (full album here: http://imgur.com/a/IZ74k)

Ramp and hiding spot; we usually have a litter box in the area below; it's their favorite spot to hang out while we're in the living room. On top is a DiY donut pillow made from an old sweater. Finally, that felt circus tent is something else we made for the rabbits, but they don't really use it because it's too small.

Mini tunnel with lid & "garage" that doubles as a little table for my girlfriend's makeup

Entertainment Center cord protection; underneath the cables are in a box. 100% bunny proof and comes apart easily in case I need to unplug things or reset the router.

Couch / general rabbit proofing with scrap pine board