Yep, looks like I will have to find an alternative for my motor shield.
In the mean time, I'm considering cheaper power supply alternatives to the balanced LiPo battery packs you mentioned.
I have almost no requirement in terms of capacity: only need to sustain 30 minutes of runtime. (Kind of a one-off thing...)
I haven't calculated how much current my Arduino will draw because my demand on capacity is going to be low regardless even if we use a number like 500 mA.
Space and weight are important factors, they should be kept as low as possible.
I'm looking at using a 1.5V AA Alkaline battery with a step-up converter to power the Arduino; and then perhaps 1 1.5V AA NiMH for the motor.
Would this have any problems? Do I need to up the Alkaline to something similar to NiMH?
Any suggestions and advice would be appreciated.