Okay, I know I mentioned I would do this a few days back, but... life. And a bad memory.

My ideas might not work for you as I don't really do formal. I am more rustic or eclectic, but what I do is I look for things that weren't really meant to be used as planters. For example, a few years ago, my MIL was pretty big into things that had birdhouses on them and decorative birdhouses. Then they decided to remodel their kitchen and dining room and she decided the birdhouse stuff had to go. My wife and I went through the stuff and I found a few decorative, heavy mixing bowls that would serve well as planters or planter foils. Rather than drill into these bowls, I set the cheap nursery pots inside. Sometimes one per bowl, sometimes 3 or 4, depending on the size of the pots. I have done the same thing with baskets and other things like a decorative tin that came with an order of mixed nuts from my daughter's Girl Scouts troupe. The nice thing about the bowls is that they double as drip trays/bottom waterers. Instead of pouring water onto the soil, pour it into the bowl and then drain in 15 minutes or so. I am even, as I type, looking at a 'birdhouse' that was made of bamboo to look like a Polynesian tower and I'm thinking that it could make a nice place to grow some Tillandsia.

I have used wood to build planters before, but I have found that you really need to protect the inside of the planter. Using a thick plastic bag works well, just make sure you drill holes in the bottom of the planter and then from the inside of the planter, push the bottom of the bag into the holes until it protrudes from the bottom and cut off the excess. This way the plastic protects the wood 'completely'. But regardless of how well you protect the wood with plastic, it will eventually develop rot. Condensation will trap moisture between the wood and the plastic and from there it is just a matter of time. Still, since you mentioned wanting a planter for papyrus, which likes moist soil and can even grow in water, you could build a wooden planter and set a small bucket inside filled with your wet potting medium. After you get the plant looking right, you can top dress with sphagnum moss or something to hide the bucket and make it look like the plant is in the wooden planter. Just provide yourself with a means for directing water to the bucket so it doesn't end up in the box. Perhaps a cut soda bottle top painted flat black so it doesn't stand out too much and nestle it in the moss.

I have seen people use inexpensive watering cans as planters and to me, using something like this painted to match your decor could be cute as you will have a water loving plant inside a watering can. Makes sense! I even saw where one woman used a small, yard sale find, teapot as a planter for her succulents. If she thought she needed to drain the pot, she just tipped the pot like she was pouring tea.

Again, this might be more eclectic than what you are looking for. But if you do something like the watering can and repeat it with the same color through the house, it could still look a bit formal while adding a little fun.

Just my two cents worth.