While I do like my Forster screwdrivers, and use them a lot, and definitely recommend them, probably my most used screwdriver is a no-name, yellow and red plastic handled, fairly short screwdriver that is probably about as old as I am. It's easy to find good quality old screwdrivers and grind them to the size and shape you want, just like Fred said.
That said, I am now on the lookout for the flat bladed "cabinet screwdrivers", which, though most all of them to be found today are late 19th-early 20th century, APPARENTLY are fairly similar to 18th century "turn screws" (?). I just ordered a couple off ebay, wanting one small enough to carry in my shot bag. Larger/longer ones are easier to find, it seems, but I don't want to make a sheath for one on the back of my bag.