I sometimes work in the garden. On cloudy days my Thinkpad display works just fine. If it's really sunny I use a Fujitsu Stylistic tablet pc I bought used on ebay, along with an external keyboard. The Stylistic tablets have (at least used to have) models with transflective displays (the ones with frontlights instead of backlights). Those are awesome in daylight, but look dull indoors. The resolution normally is not that great, but for ssh it should be just fine. Still kind of unwieldy, though :/

Hah, I just remembered that my alternative would have been a netbook modded with a Pixel Qi display from Maker Shed. Maker Shed does not seem to have them anymore, but perhaps you can find one of the prebuilt devices with pixel qi displays: http://www.pixelqi.com/devices

edit: I cannot recommend working in nature enough! I'm usually both super productive and in great mood while working outdoors.