Highball boulder problems are kinda a thing into themselves. Sure, they are just a really tall boulder problem (or a really short route), but the head games are all different.
First, unless you set up a toprope, there is no way to suss out the top moves. Every time you have to start from the ground up, working your way as you go (I believe this was/is John Gill's moto as well). Similarly, because you are not roped in, but easily getting off the deck, the mental component of the route really comes into play.
Yesterday Tara and I went to try out a really nice highball problem that I had noted last fall. Located on the backside of Green Mountain in the Boulder Flatirons, this problem is really a classic.
Start on the arete, pull up with your right hand to a good hold, then reach out with your left to a good sidepull. From here, get a high right heelhook, reach across to a nice three finger hold, and then pop up to a small left hand gaston. From here you are well off the deck and teetering on the final couple crux moves. The top out is 20+ feet off the deck, and the problem does not let up.
It didn't go, but I got pretty close. I'll need to come in with a couple more pads - I only had one Metolius with me and after taking about 10 falls 10 feet off the ground, I had enough. The hike is about 30 minutes, so it is not that bad but long enough to make you think twice.
Lots of other good lines waiting to be done right in the same area. We need some of the strong kids to get inspired by the vast potential still waiting in the Flatirons (some are in the forthcoming Rocky Mountain Highball movie). There are still tons of undone, very hard boulder problems waiting to be had.