Good motion tracking for a Bosch generation 3 autodome?

[tomster 0]

I've got a Bosch Gen 3 0948/25C envirodome (PTZ) used in conjuction with an LTC 8786 biphase converter attached to a DesaXL DVR. My autodome is capable of tracking, but you have to get an additional (optional) power supply to add tracking to make it work. Is there a decent way for me to add auto tracking to my autodome without spending the $800 for a bosch tracking power supply?

 

I see that there are standalone modules that add autonomous PTZ motion tracking (such as ioimage). I see stuff like this on ebay from time to time for far less than the cost of the optional Bosch tracking power supply. Is this stuff any good? If so, can you recommend the best all around product to give me autonomous PTZ for my dome?

 

Thanks