We replaced an old batten-and-board ceiling in the master bedroom of my old house - an 1870s funeral parlour. The house has spread about 10cm, and some idiot 5cm of spread ago cut the battens really badly to put cornice in, so there was a hefty gap we couldn't sensibly fill. And the battens and boards weren't very good quality in that room anyway so it wasn't worth restoring them, despite them being cedar.
Our main problem was the ceiling joists were over a metre apart - way too far for plasterboard. So what we did was take down most of the battens and boards (oh, the DUST) and doubled them up (to get the required thickness) using decent screws not ancient square nails to make mini joists that were close enough to put plasterboard on. Basically just did this because it was cheaper and easier than buying new joists. The end result is a lovely, modern looking ceiling that doesn't let dust in, and hasn't fallen down yet. We did it about 3 years ago now. Whole thing cost $500.
The dust in old rooves is incredible - ours was so fine it behaved like a liquid. If you left some on a plank and tapped the plank the dust would actually bead up, like water on a freshly waxed car bonnet.
I'd love to get another big old commercial building but the town I live in is very short on them. There's a seriously cool church for sale the other half thinks is Too Much Work and keeps telling me off for drooling over but otherwise it is all houses *sigh*