The E39 BMW 540i MSport came with a TV. Unfortunately the earlier models had an analogue receiver which became defunct after the Digital Switchover to DAB. There are some third party solutions out there, but for convenience it is easiest to just switch the receiving module, which is located in the boot. This blog concentrates on how to update the unit to a digital receiver.
Choosing the correct module
Make sure to get the correct one. I remember there being issues with both the connectors and the mounting flanges. As there were a couple of variants, it was easy to purchase the incorrect and, hence, ill fitting module.
You also require the I-Bus (Instrument Bus) version:
This does not seem quite right: http://www.bimmerforums.co.uk/forum/f8/e39-540i-freeview-digital-tv-t142450/
There are a number of these units on eBay.
There are some other addons which are note worthy. Such as: