We just finished doing a group run of these through some professional knitting company in the UK.
Due to how well they came out interest is still high and we're 6 people into another list for a 2nd run of these (12 minimum is required). If you like I can add your name to the list. Just PM your email so I can contact you once it happens.
Pics and info here:
http://community.livejournal.com/dw_cosplay/221664.html
Otherwise as the 2nd poster said your only option is to custom commission one (to the tune usually of $200-$300) or buy a standard cricket sweater on ebay in the $15-$40 range but look for the vintage 80's styles that have the black-red-black v-neck stripe which is the closest a commercial seater ever came to either of the Davison Season 19 or 21 style.