I have a small NYC 5 X 8 bathroom and need a 30 X 60 alcove tub under 15" high as it's mostly used for showers, and a taller one is too hard to get in and out of as I get older. I'm doing a higher end look, and it's discouraging that these two seem to be my only choice. No room to build a surround.

Are there any others? Would prefer cast iron, but any material that will hold up 20+ years would also be fine. Any ideas? Thanks!