If you're looking to make some dark wood, you can also burn/scorch the surface. If you google "shou sugi ban" there's some information on it. It's Japanese style of finishing that's more intended for construction. You basically scorch the surface then brush off the ash. It turns it black and brings out the grain pattern. Also makes it fire/bug resistant. I tried it out over the holidays on some small pieces of cedar. Most of these I just barely hit with a torch, but the black ones I just spent a little longer. They look like ebony, but it's not expensive. It's only a surface treatment though, so when you cut the wood, your back to regular wood. Might not be that different that dying wood though. I ended up getting a roofing torch and scorching a bunch of 1x6 pine boards from Home depot. They look really nice (and jet black). Plan to much some outdoor planters when the weather warms up.
All of the poly finishes will be more protective, but I love the feel of the wood itself, preferably not coated in thick plastic. If it's your desk and not a general conference table then I wouldn't rule out an oil/wax finish. You don't have to worry about streaks or brush marks or drips because you just buff it off. My current favorite is Odies oil which makes the grain stand out, but since it soaks in, you're still feeling the wood and not the finish. If you want it a little more protected, then I'd just add some extra wax. That said, if a lot of people are using it, then go ahead and seal it up. Anyone who hasn't finished their own table is probably not going to be too careful with coasters or spilled coffee.
These look great, especially to see it go from Sketchup to actual furniture. I think the finish looks good. I'd be afraid to try to do anything to the bottom now for fear that it would screw up the finish on the top that looks so even. Maybe hand paint the bottom if you really wanted to, or clear coat the whole thing?
ran into it one time which was painful, but I learn fast, no problem since. You can also make them much shorter. There's no structural reason they need to stick out, I just liked it.
The joint is rock solid because it's about 4 inches deep. I was expecting some movement, and nothing moves. The entire rails are actually resting on the flat bottom of the grove I cut out on the router so it's really stable. There's no hardware that holds the rails to the legs. When I was setting it up, I did run into problems with the rails bowing out and allowing the slats to fall through the middle. I was going to fix that with some pegs that would secure the rail to the slats, and I'm still planning to. Once I put the mattress on it though, it's a foam mattress and it basically secured the slats from moving in any direction. Hasn't been a problem since.
Agreed, I like the when the wood just fits together. Since these didn't get glued together like a mortise/tenon, it was also a lot more forgiving putting it together.
Still haven't been able to teach him to use it though