Has anyone installed ABS on an ACVW?

[Simon]

There are independent ABS ECU's available, for example from Bosch, see:
http://www.bosch-motorsport.com/cont.../html/3490.htm
The price quoted on the Bosch site is EUR 5350,00, AFAIK it can be had a little cheaper (like EUR 4500), but basically it's really expensive

They are for motorsport use though, so sensors on every wheel (you could use them as an electronic "diff"), and they can be programmed exactly the way you want it with the included software.