I use, when traveling, an old Samsung nc10 with OpenBSD: https://en.wikipedia.org/wiki/Samsung_NC10
I like it a lot, but unfortunately firefox is too bloated for it. Any recommendations? The lighter, the better. 10'' monitor is perhaps the best size. Matte screen is important, I read a lot. I would buy a used one in ebay. By the way, does any tablet PC work with OpenBSD? Thanks Rod.