Has anyone seen www.trackaccesssolutions.co.uk?
They have free demo clips of cab rides which synchronise with a rolling signalling diagram display as the train progresses.
Clips include Heathrow Express - Hayes & Harlington to Ealing Broadway. Eurostar - Swanley to Channel Tunnel.
Northern Line is in production.
These are primarily aimed at the training of Rail Staff and thus I would imagine the price for the full version of these would reflect commercial rates.