Can you give a little more description of your current bathroom setup? It's an Eichler, correct? Do you have a wall-hung sink or a vanity?
If wall-hung sink, IKEA has cabinets that fit under wall-hung sinks. I make no recommendation on the designs, I just mention you might find a solution there. Also, a friend in a Cupertino Eichler replaced his wall-hung sink with a special ordered IKEA *kitchen* cabinet, ordered for its smaller width/depth than standard vanities. If you special order, you can indicate whether/which sides you want a kick on. He then chose a countertop/sink/faucets.
In my Jones & Emmons atrium model, I also had issues with bathroom storage. My setup has a walled vanity area flanked by a master closet on the left and the toilet/shower enclosure on the right. The mirror over the vanity in my model is flat glass (too much framing and pipes to have a recessed cabinet there).
- I hung a medicine cabinet on the wall to the right of the sink,
- put a base cabinet on the open wall of the U-shaped closet (two walls contain the L-shaped clothes rods) and
- added 2 standing garage cabinets in the garage immediately adjacent to the kitchen/garage door. One standing cabinet acts as a pantry/bath storage and the other stores tools.
I frankly could not fit all bath/medicinal items in the master bath itself.
Hope some of this is helpful.
P.S. I got my medicine cabinet from Topdeq but Chiasso has something similar. Fixed shelves and quite narrow so really only useful for items that need to be locked (prescriptions, etc.) Still, it serves a purpose.