Actually, there are several powerplant/prop harness-units commercially
available for use with hang-gliders. While their use is still contraversial
(is it an ultralight or HG?) the USHGA has ruled to include them in our bylaws.
The condition is that the powerplant is intended for climbout only, with the
primary power coming from soaring thermals.

I've also seen several self-lanuching "motorgliders", two of wich were
performing aerobatics at airshows.

As for a canard glider, I suggest you check out the photos of my Wright 1902
glider on my website. Best glide for the original was 622 1/2 ft. launching
from a 100 ft. hill... World record in 1902. Still extremely unstable, but
that's half the fun!

Harry
http://hometown.aol.com/wright1902glider/airshow.html