Bit of an impulse purchase this but I found it on offer for £26 delivered,
Sealey BG1010
Around 8" / 20cm wide, it has a coarse & fine wheel fitted, variable speed, slow start, flexible shaft for dremel type tools or drill bits that can connect to either side, and an additional piece (not pictured) for mounting the wire wheel, polishing head or red "scotchbrite" type wheel.
I bought it mainly for the flexible shaft as it's got to be easier on the wrist than my heavy budget tool but I'm sure the other bits will come in handy.