i have seen this with enameled steel tubs. i do not recommend them. The apron is a separate piece of metal.
i have heard from an acrylic tub maker that anyone can cut an acrylic tub into shape to suit as long as he supports the remainder properly and without expecting full warranty. I believe that.
I don't know what make is available to you in your area but it shouldn't be a problem.
I carry Alcove and they are not a large company and they make them.
Most of the drop-in tubs have a tile flange kit that can be added at installation time and there are ways to perform that function without a flange using specialty trims and membranes (look at www.schluter.com for Dilex when used with Kerdi for waterproofing the walls as one example).
I have exactly what you are describing -- we're installing it this week. It's made by Hydro Systems (www.hydrosystem.com). They do a lot of whirlpool tubs, but you can order any model without this option, and also specify the integral tile flange. Ours is 60X30 (Lacey), but even more choices available in 60x32.
All these tubs are made to order, so they're not cheap and take a while to get what you want.