Dont really think there is any happy medium for you. If you fear
the plumbing will go on you, then have it checked or replaced.
If you want a nice smooth surface any and all contractors are going
to say put up drywall. nice thing about drywall is that it can
be hacked up and replaced smooth again with a little bit of
work.

I looked at the 2x2 tiles too. Didnt really find anything that
appealing.