It depends what you call cheap, but you may look for the 135 versions of the Horizon (ie S3 or 202, no shift as far as I recall), they sell for a few hundreds bucks generally... The 120 versions of Horizon of Noblex are generally in the same price area as the 617, at least the chinese ones (ie thousands and not hundreds).
You probably already know it, but beware that rotating-lens cameras as the Horizon and Noblex give you a cylindric projection (ie curved horizon when not centered, can be dealt with some shift) and funky effects on moving subjects ; this is what you pay for a perfect optical homogenity across the widest dimension of the frame.
Otherwise, dealing with the limitations and powers of stitching may be the cheapest way to do it (the cost of a basic pano head as the Panosaurus or Nodal Ninja is an order of magnitude below the aforementioned MF cameras, and it's not even strictly necessary).
