Made this as my ABS was suffering from moisture absorption causing poor prints.
The tub was £3 from Asda and just the perfect size, the axle was just a piece of wooden clothes rail from an old wardrobe (or you could use PVC pipe) and the axle supports were printed in ABS at 0.3mm then screwed to the inside of the tub (diameter of the axle rod is 22mm, inside diameter of supports is 22.5mm and the screw holes are 4mm).
I have a bag of silica gel in the tub to help reduce moisture.
Update : Stoppers - these are a tighter fit than the supports but can still be moved along the axle to fit different spool sizes. They stop smaller spools from moving about while printing . Printed at 0.3mm.
Filament feeder - 2mm diameter nozzle for 1.75mm filament. Mine is pushed through a hole in the lid and glued to the inside or you could just glue it to the top. Printed at 0.2mm.
I used 123D Design for the 3d modelling.