I received a new toy earlier.
It's a "vortex" mixer to replace the £20 ebay job that proved that it'll work mix model paints (not meth, honest!) but the £20 job only lasted about a minute of use...
The difference between them is night and day, and the big guy only needs to save me rebuying about 20 bottles of pain to pay for itself*, let alone the time/effort saved in just general shaking of paints before use.
I've got a couple of the adaptors for it as well, and I think i'm going to make a custom adaptor for the beaker plate to hold something like 3 GW or 4 Vallejo style bottles.
*Unlikely to be an issue for it to reach that, given GW paints tend to settle badly after a few months, and my brother and I have hundreds of paints.