Thank you all so much for your answers. I guess that my options right
now a

1) Modify the bathroom door to open outward instead of inward,
allowing me to install the 38" unit Travis Jordan found:
http://www.faucet.com/cgi-bin/product.pl?mid=457.

Pros: 1. will get me a more roomy shower.
2. will save me from power hammering the concrete slab.
(*if* 8-7/16" is not too much of a deviation from 8")
Cons: 1. will have to modify the door (unplanned work).
2. will have to cut the existing tiles on floor to fit the
different line of this 38" shower.

2) Order a custom unit (per Bryan's suggestion).

Pros: 1. least headache.
Cons: 1. probably most expensive solution?
2. longer lead time?

3) Moving the drain center by chiseling the concrete slab.

Pros: 1. will allow me greater flexibility in picking from
a variaty of products.
2. perhaps will free me from being locked into the
existing non-standard solution? (if new one cracks too).
Cons: 1. Messy. Too risky for me to do. I will probably have to
hand this over to a professional (plumber? builder?
what kind of a professional?)
2. Due to labor involved, probably most expensive.

4) Moving the drain center by raising the base on a platform.

Pros: 1. will save me from power hammering the concrete slab.
(*if* 8-7/16" is not too much of a deviation from 8")
2. will free me from being locked into the
existing non-standard solution.
3. Probably the least expensive solution.
Cons: 1. Ugly. Weird.


Any opinions? Comments?

Thanks,
Lynn