[quote name='JapanAxe' timestamp='1396025595' post='2409205']
OK, found the specs for the Seymour Duncan SPB3 on their [url="http://www.seymourduncan.com/products/dimensionpages/spb-3.shtml"]website[/url] and the 'body' of each part of the pickup measures 2.25in x 1.09in. The corresponding Yamaha part is 2.20in x 1.09in, so pretty close - the SD is 0.05in (i.e. 1/20in) wider. These are external dimensions of course, so I still don't know whether the SD innards would fit in the Yamaha covers (or indeed whether SDs are that bit fatter than Fender originals on account of the chunky pole pieces).
Also brought up the [url="https://bareknucklepickups.co.uk/main/downloads/dimensions/bass/p_bass.pdf"]Bareknuckle[/url] specs. They give external dimensions of 88.50mm x 25.44mm, which must be wrong as it is 3.48in x 1.00in - I reckon the first figure should be 58.5mm, making the dimensions 2.30in x 1.00in. More usefully, the bobbin dimensions are given - less usefully, these seem wrong too!
[/quote] Could Bare Knuckle or A N other make you something custom that would not cost the earth ?