The two CDNs that I'm most familiar with (Akamai and Cotendo) do offer CDN/DSA services over SSL. I would imagine that the other big CDNs also offer SSL service. (Otherwise, how would they compete for e-commerce business?)

We pay Akamai a non-trivial amount of money for SSL service, and they in fact host separate certificates for us (in addition to our origin servers hosting "our" own [different] certificates).