The LXD snappy package is not yet currently available as a general release image for LXC. What is however availble is a snap for testing LXD on snappy - stgraber has posted about this here:
A binary for amd64 can be downloaded at:
Then installed with:
snappy-remote --url=ssh://localhost:8022 install lxd_0.11-git0_amd64.snap
But this only helps you get started running other containers on snappy, not with loading snappy in LXD.
A good place to start the dialogue about what you would like to do would be the ubuntu mailing lists for LXD, or perhaps file a bug against the LXD project requesting a snappy image be published for consumption, where the team can then build an image, or request CPC build one.
Anything beyond that will be an exercise in manually building the LXC rootfs and containerizing it. YMMV