There's a new kid in town that provides a viable alternative to the M3 Steering Wheel. It's the M-Sport Wheel that BMW have begun fitting to the X3 but I got one of the first in the country and fitted it to my 4.8is.
The part number here in the UK is B32.30.3.415.380 with a description "004183/M strng whhl". It costs £251.06 plus VAT here in the UK.
It's much chunkier than the standard item (perhaps even more so than the M3 wheel) and more attractive IMO. The //M logo is nice and it uses a soft nappa-like leather rather than the more industrial quality material on the OEM Wheel. There's a slightly squared off feel to the rim and the thumb holds are more pronounced.
Anyway here's the pictures...
This is a comparison of the old steering wheel next to the new M-Sport Wheel. Note the chunkier rim, narrower bottom stem and better quality leather