Arriva Trains Wales are proposing a 2 trains a day weekday direct service from Aberystwyth to Marylebone (with 3 trains on Summer Saturdays) via Shrewsbury using refurbished 158s.
The proposals are here:
http://www.networkrail.co.uk/browse%20documents/track%20access/1%20current%20consultations/2008%2012.20%20arriva%20trains%20wales%2034th%20supplemental%20agreement%20-%20closing%20date%20for%20responses%2023%20january%202009/aberystwyth%20proposal.pdf
The proposals are here:
http://www.networkrail.co.uk/browse%20documents/track%20access/1%20current%20consultations/2008%2012.20%20arriva%20trains%20wales%2034th%20supplemental%20agreement%20-%20closing%20date%20for%20responses%2023%20january%202009/aberystwyth%20proposal.pdf