[SunkenCiv]

2004 MN4
http://neo.jpl.nasa.gov/risk/2004mn4.html

Here are two more; the Near-Earth Objects (United Kingdom) website shows both as needing more observation, and the latter as having been "lost" after its 1997 discovery.

2004 VD17
http://neo.jpl.nasa.gov/risk/2004vd17.html

1997 XR2
http://neo.jpl.nasa.gov/risk/1997xr2.html

Biggest Threat So Far In Most Ways
Posted by Mark Eby on 12/24/2004 7:43:40 AM
http://www.habitablezone.com/space/messages/362407.html

"1997 XR2 is a practically permanent list member because it has not been tracked since 1997 after only 44 days of tracking. 2004 VD17's more specific Palermo scale ranking has been stable for several weeks after a similar period of observation with about 4 times as many individual observations and will probably take long term observation to eliminate from the list."

[SunkenCiv]

These results were computed on Jan 28, 2005

2004 VD17

1 in 7,690 chance overall

May 4 2091, 1 in 12,000 chance

These results were computed on May 29, 2002

1997 XR2

1 in 10,000 chance overall

Jun 6 2101, 1 in 19,000 chance

Jun 6 2101, 1 in 22,000 chance