I have a Beacon Walker/Exerciser for sale.  Its the largest one with Manual lift.  I have used it for my Dobes, but I am now coming out of that breed and do not require it for my new breed.  Its has been a god send in getting the dobes fit for the ring and they love it.  Has the safety cage all round, with digital read out for speed, time etc.  Cost £1800.  Offers in the region of £700.  Space needed.
Contact me for furtehr details. Mandi on k9weg@aol.com