1. Yes you cannot remove the cable modem
2. Cable modem are supplied by the cable company and all use a difference type of modem
Have not seen any combine cable modem/router sold
3. You will have to use the cable modem with a DSL/wireless router, which will connect to the modem via the Ethernet WAN port all you, would be adding is the router and a short Ethernet cable
At the moment only the ASDL service via the phone line can you buy a combine modem/wireless router and only in Europe?
In other part of the world you will have to use an ASDL modem plus a wireless router, which I previous used, before I bought a 240 volts 3com ASDL combine unit in the UK installed via a 110-240 volts transformer and still working perfect