They were never available in the US, BMW is releasing it's first four cylinder engine in quite some time in the US later this year when the Z4 sDrive28i debuts.
Originally Posted by ProRail
Can't get them anymore in the US, but there are plenty in Europe. Hope somebody on your side of the pond will chime in.
Current - 2012 135is DCT
2009 Mini Cooper S 6 Spd
2006 M Roadster
2004 645i SMG
2002 330i 5 Spd
A bunch of cars not worth mentioning...