These are the ones I have which were the usual commercially available ones, although I think they may now be out of production. I still see them on Ebay but for how much longer I don't know -



There is also the "Glenfinnan" type which is made to look like an authentic historic type of 18th century shoe, illustrated here -

http://www.scotweb.co.uk/sr_macfr_glenfinnan

but at nearly £200 are a lot more expensive.

We also have an accomplished "souter" here who showed his workmanship recently and very good it was too. Don't know if he takes commissions but you couls always ask. DWF11 I think he is.