I know of a couple of VPS providers that support BSD distros (rootbsd and prgmr), but I'm wondering if anyone has any other solutions they'd recommend? Moreover, I'm very curious why BSD support in the VPS world has been lagging behind Linux. I know the supply/demand may be different for each, but is there a technical reason that it's slow to adoption?
At the moment, BSD VPS providers seem pretty few & far between. Here are a couple I've found that provide FreeBSD:
It seems like there probably isn't as much demand for BSD based servers right now... but perhaps that will change in the future.
DigitalOcean.com is a major vendor of virtual servers.
In early 2015, the company launched a major revamp of their architecture to support FreeBSD VMs as well as their previous Linux VMs.
See their blog post announcement for details.