The CD player can be mounted in various places. People on here have even mounted their Head unit underneath the passenger seat for security.

Not my cuppa tea, But its safer I guess.
The cheap route would be to get a Under dash CD player housing, can get them from any mini spares place for about a fiver. It mounts underneath the Dash rail on the passenger side.
Another idea would be to buy/build a center console, and chuck it in there. Like I did.

A good alternative if you want to run Center speedo!

Other than that, theres the most popular choice, The dashboard.
I had a dash mounted Sterio in my first two minis.
