Having looked at this somewhat with an eye on including ABS in my build, the modern (Bosch) DSC systems are integrated with ABS, the latest 5.7 system basically consists of four wheel speed sensors, a yaw/acceleration sensor (the 'combined' sensor), a steering angle sensor and the main unit which has the pump, solenoids and combines traction control, ABS, DSC and EBD.
This is the diagram for an RX-8 for example (chosen as its a mid-engined RWD car with a very low CoG).
The same systems are used on a vast number of cars, parts are common between many makes and models.
As far as I can tell, as long as you have the four wheel sensors the ABS should work (if not ideally). As should EBD. Traction control would have to have a compatible PCM (ECU) or some kind of CAN bus bridge (the HU/CM DSC module requests a power reduction over CAN).
DSC becomes rather tricky however, along with requiring the wheel sensors and the same CAN bus bridge (or compatible PCM), now assuming you fit the yaw/acceleration sensor in the right place it should know what the car is 'doing' in 3d space, what won't however match on a totally different car is steering angle which means that depending on geometry you could potentially get the computer interfering
well before you are anywhere near loss of control, potentially fatal if (for example) it causes you to understeer or oversteer off the road.
After all that is said, I know that someone sells an aftermarket module for the RX-8 that allows you to tune the over/understeer of the DSC. I know that the RX-8 HU/CM needs to be configured for the car if replaced/swapped. I know that Audi's have settable parameters[1] (Same Bosch ABS/DSC unit as used in the RX-8) and it's meant to make a noticeable difference what brakes you 'code' it for. So with that in mind I went a googling and finally, I found this
Bosch Motorsport - Software which is a piece of Bosch Software called RaceABS, it seems to allow you to set individual wheel circumference, trigger wheel count, weight, track, wheelbase etc etc.
Downside is it needs something called an MSA box which while "low cost" maybe in racing terms is still 720Eur! If you get that then you should be able to reprogram the ABS/DSC to your car.
Personally I bought a s/h HU/CM off ebay for £1 along with a steering column/wheel and sensor for another £1, I'm going to set it up with some hydraulic switches, rig up a way to fool the wheel speed sensors and see what it does. Maybe it'll work, maybe it won't but I'm not spending 720Eur on a diagnostic connector!
D
[1]
http://wiki.ross-tech.com/wiki/index.php/Audi_A4_(8E)_Brake_Electronics_(Bosch_5.7)