This subject came up a little while in the postprocessing/software forum; although nobody with the 10-17 zoom posted a response, you might find the discussion useful:
10-17 de-fishing resolution loss?
It's mathematically impossible to have a rectilinear image with 180 degree FOV (the corners of the image would be infinitely stretched out); other projections can give you the 180 degree FOV; these generally straighten only vertical elements and produce very interesting geometric effects.
You could do a rectilinear projection of a zoom-ed in image from the 10-17; you would get about a 90 degree horizontal FOV. Image quality may be adequate for your purposes but won't be as good as an image from a rectilinear lens (particularly in the corners).
My advice: if you like fisheye look (I assume you have found the Fisheye Fever thread by now), and you think it would work for your subjects, get the fisheye.
Otherwise, go for the ultrawide rectilinear.
BTW, the Pentax 12-24 and Sigma 10-20 both zoom in to a pretty useful ordinary-wide-angle focal length; this would be quite useful when you're trying to minimize lens changes.
** EDIT -- I just noticed from your signature that you already have the DA14! In this case I suggest getting whatever you want and skipping this rectilinear conversion stuff entirely!