It has been some time since I was doing stereo photography, but yes, you could use a pair of SLRs, the issue being that the inter-ocular or inter-lens distance would be greater than required -- you'd be into hyper-stereo territory. I once had a pair of Rollei 35S camera that I could mount on a platform; because of their small size, the inter-lens distance was less that it would be with larger cameras. If you look at the RTB link in a previous post, you'll see that some experts actually merge two cameras into one.