You could also consider tongue and groove pine. Where you would need to access those things, take the tongue off the wood and rather than toenailing the wood up, you could anchor it to the joists with a few nicer wood screws.
Hmmm, or instead of the tongue, take off the bottom of the groove; then the overlap would look the same, but the piece would be able to pivot out of place.
*snip*
I don't particularly care for that style in this image, but it should give you another option to think about. (A lot of the wood is "reversible" - the opposite side of in this photo could be the visible side & would be the full width of the planks.) If you do decide to look into going that route, be aware that the box stores (Home Depot, Lowes) are a hell of a lot more expensive for tongue and groove vs. lumberyards. We did a vaulted ceiling in our house and found that an 8' section at HD was $7.99, while a 14 foot section at the lumberyard was under $4.25. Coverage is 5 1/8" wide (on the stuff I have.) Do-it-yourself installation with one person is a hell of a lot easier and quicker than either drywall or a drop ceiling. A quick back of the napkin calculation shows that 2 years ago, it worked out to less than $1 per sq foot. I don't mind finishing drywall, but I hate finishing drywall on a ceiling.