well, not exactly transcription companies,
but i found a website which gets all freelancing jobs from the major freelance sites like guru.com, scriptlance.com, rentacoder.com and all major sites and others.....into your inbox.. www.freelanceprojectupdates.com
( no affiliate link and its not my site )
hopefully this will help, if you think not then you may delete this post..
thanks for the big list