Dream doesn't have much of a system call dependency footprint itself. It's basically just a convention for plugging request -> response functions into a web server. Some of its native dependencies will have to be replaced by Node equivalents. Soon after that, it would be portable to Node.
There is already work underway to port Dream to Mirage, to run in unikernels: https://github.com/aantron/dream/pull/22
Lwt, Dream's promise library, is itself getting ported to run on top of libuv: https://github.com/ocsigen/lwt/issues/813
libuv is, of course, the I/O library that powers Node, so it might be practical to run Dream as a native node module very soon after doing this.
(As an aside, I'm supposed to work on that libuv project, but instead I've been working on Dream :P)