Sorry to hear about your spine problem Deane. Hope you feel better soon.

You might consider a good priced PA800. That is an awesome machine that is closest (IMO) to the PA3X. I had the 900 and thought it was a lot of corner cutting in comparison to the 800.

The 3x is big, but I'd rather have a 'slim' footprint. Even with 76 keys, I find it easy to tote around vs the smaller, bulkier units.

76 keys is the ticket and DON'T forget about the tilt screen. That is worth the money for my neck issues.