I put mine in my medge case that I had for my Sony 505 (I think it's the same one they sell for the PRS-600). It fits ok - it is a bit shorter than the Sony so the top straps just barly loop over the top corrners, but it does hold it pretty secure. I have the executive jacket, but they have different cover that would hold it in theposition you wanted.
http://www.medgestore.com/products/prs600-platform.psp
HTH. I'm happy with this setup for mine (for now) but when they release the cases that are specifically for the Kobo Touch - I'll be buying another cover from them.