My first post. Happened upon this place accidentally when I was searching a similar subject.
The green coat is not custom. In an interview the decision to use it was based
entirely upon matt smith already wearing the jacket when Moffat turned up
on set one day and thought it would be perfect, so it's Smith's own coat.
Knowing this, i knew what to search.
His coat is a (US) navy peacoat. He wears
a blue version in promo shots and
happened to be wearing the green
one one day during rehearsal.
Moffatt liked it so they rolled with it.
EDIT:
FUll length pea coats are not easy to
find. If you wanted an easy option,
a US Navy 44inch Bridge Coat would
be a close match, but only comes in
blue as far as i know.
Matt's boots custom, but All Saints layer boots,
very close and easily modifiable from
thereon.
His jacket is a custom, i believe, but is
made from readily available Shetland Tweed.
Hope this helps.