In the absence of ready cash to buy a new scanner, I’ve finally found a photo shop which is capable of decent, low cost medium format scanning. Photo Vision, in the Marktgasse in Bern, offer 16 bit TIFF files for Fr 3.50 each, scanned at a purported 4,800 dpi to produce 80 megapixel files. This is an example of an uncorrected scan I’ve just collected. (Click on "all sizes" to see the picture at 1:1 resolution.) A tip, though: make sure that you specify that the automatic dust, colour and sharpening correction is OFF, otherwise the quality of the image at full resolution is noticeably compromised.
The photo itself is about ten years old, taken of strangers on the northern bank of the Thames in London, opposite Battersea Power Station.