We have discussed many options for the included soft case that comes with our S-12 harp guitar.  It is difficult to find one that works since there is no real mainstream case maker that makes an affordable gig bag for harp guitar.  The closest we have found is a 61 key keyboard case of some kind, and I think we have finally found our winner:

This is the Ultimate Support System One keyboard soft case.  You can actually purchase them at some Best Buy locations, but they are a very ruggedly constructed exterior with lots of pocket space.   It also has a Velcro securing strap inside to help with holding the instrument in place.  This should be a great fit for most any harp guitars and will be included with our S-12.  If you prefer to have a hard case, we have that upgrade option available as well, with the Gator GKPE-61