I looked at the Kohler tubs and didn't see anything that matched it.
As you mentioned, looks like the Empire tub by Waterworks:
http://www.waterworks.com/products/fixtures/bathtub/freestanding/freestanding-rectangular-bathtub-70-x-34-x-24/380
:) Rhoda

Darn,that what I thought. Isn't it gorgeous?

Here's a tub that also resembles the one shown above.
The Michelangelo maestro series by Hydrosystems, which is one of the brands carried by the design center:
http://www.hydrosystem.com/article/141/bath-collections/maestro-series/michelangelo

I agree, definitely looks like the The Maestro Collection Michelangelo- http://www.qualitybath.com/product~name~Hydro%2BSystems%2BMMI7036ATO~ID~71771.htm

This is the Michelangelo from Hydrosystems. It retails anywhere from 7-9k depending on the options you buy, bubbles etc. It's beautiful and very well made, but a little pricey. Hope this helps. Charmean Neithart

Been offering this wonderful option to my customers now, it's under $5k and is not acrylic, it's Aquatica CrystalStone which is a composite material that consists mostly of mineral fillers bonded to polyester resins and acrylic polymers. The result of this particular combination is a “soft-touch” surface that mimics porcelain’s high-gloss white finish and a natural stone esthetic in a surprisingly lightweight and durable form.

http://www.poshhaus.com/store/p/7266-Aquatica-Aquatica-PureScape-510-CristalStone-Freestanding-Stone-Bathtubs.html

We carry Waterworks and I do not believe that is the Empire however does look very similar. We also offer another line and they have a piece that is very similar and much more affordable. Please email me if you would like to get pricing and additional information at alissa@cabochontile.com.

Thanks again Nicole

PoshHaus, Thanks for your link to the Aquatica version of this tub. Unfortunately, think link no longer works, and I can't find the tub on Aquatica's website. Do you have different source info? I notice your comment/post was only 3 months ago, so I'm hoping this isn't a discontinued item. Thanks so much for your help!

I have seen a similar tub at www.signaturehardware.com and also check out Victoria+Albert tubs. www.vandabaths.com

p.s. signaturehardware.com definitely has a very similar tub under $2000 but then add for faucet, drain, etc. I have purchased from them before and visited their showroom when on a trip to that state. Nice people, easy to work with. ... I did not see a similar tub when I viewed Victoria +Albert. I have a Victoria + Albert tub, the York. They have lots of tubs but I didn't see this exact style at their site, vandabaths.com. There is another site tubz.com that has many styles as well. Good luck!

This closely resembles the MTI Parisian or Parisian 2 depending on dimensions. They are a wonderful company to work with and have many styles to choose from. I don't have room for one of their freestanding tubs, but am considering one of the others from their line. MSRP is between 7k and 10k on that particular model.

http://mtibaths.com/products/tubs/designer/MTDS-146

What fabric is that on the windows?

Our Roman tub has been available since 1998 and is based on the antique it truly aspires to be, made from a poured mold rather than vacuum formed to be able to attain the tight curves.

who manufactures your Roman tub? I'm in Washington, DC, and am looking for a source

The Roman and Roman Petite are made exclusively for us. As each tub is hand made we do not sell wholesale, we sell direct to our clients and their tradesmen (be it Designer, Architect, Plumber or Builder etc).

We sell this tub/ please feel free to contact me