I recv'd Gold Medallion through a DL challenge back in March '05.

I faxed my NW statement which showed Gold Elite and they responded with a challenge.

The challenge: fly 5000 miles to receive Silver Medallion, fly 10,000 miles to receive Gold Medallion. All within a 3-month period. The fax said that all fare classes are equal for the challenge (unlike the AA challenges), but over the phone they said that deep-discounted fares are not eligible.

However, after 10,000 miles worth of flights posted (which were all flown on LUT fares), my Gold status appeared.

I'm not sure if the challenge is still being offered...