Mad Hatter Imagery wrote:
Where does one find a seamstress? Do tailors build clothes from scratch?

I would look for a seamstress or tailor local to me.

I would expect seamstresses and tailors to be able to alter clothing. Some tailors might create custom clothing from scratch. You should discuss this with the individuals that you are considering to employ.

Many clothing stores will alter clothing that you select off of the rack.

Mad Hatter Imagery wrote:
Where does one find a seamstress? Do tailors build clothes from scratch?

Ask around in the NYC garment district or your local dry cleaners who they use for repairs.  I see a lot of alteration shops in LA who do that sort of stuff too.

Yes, tailors make clothes from scratch from fabric swatches. My brother-in-law always wore custom made suits where he'd stand there and some Italian guy with a tape measure around his neck would run around him and get his all his measurements for a suit they'd make.  They weren't cheap though even back then and probably run as much as a custom wedding dress now too.  Some exterior fabrics hit $135/yd easy and add another few yards for some lining and those costs  plus their labor and you can hit $2K easy.  It's why the Asian knock-offs do so well, but then you may need the seamstress to alter them.