There are some particularly wacko guitars on eBay right now, which is good news for this blog. This 26-string harp guitar is an acoustic with two six-string necks - one steel-strung, the other nylon, a set of six sub-bass strings and a set of eight treble strings. I understand the concept of sub-bass strings, but I'm not sure what you're supposed to do with the eight treble strings on the lower part of the body. Tune them to a chord perhaps?
The guitar is being sold by the ebay seller tropicalmoonmusic who have in the past sold some crazily-designed guitars from the Tennessee brand which have turned out to be very shoddily built and virtually unplayable. This harp guitar is very likely from the same source, even if it doesn't carry the Tennessee brand name. If you click through on the link and look at some of the other photos, it does look rather cheaply built. Look at the back of the two six string necks. They are virtually square.
It looks like fun, but I'd approach this guitar with caution.