Hi Clint; If you're happy with the lenses you have I think there is no reason to switch brands. We have a few members using the *ist-D professionally who seem to be very happy with it. You might look for a used PZ-1P (Z1-P), debatably Pentax's most professional 35mm body. It will use both lenses with and without aperture rings, works reasonably well with MF lenses, and has a reputation of being very dependable. I've had mine for about a year and have been very happy with it. Your M series bodies will make fine back up bodies.
Butch Each man had only one genuine vocation - to find the way to himself. Hermann Hesse (Demian)
