Hi John,
A Nasa study of the TU-144 published in 2003 states that the constant alpha approach speed was 170 to 181 kts with Canards and 200 kts without. The document can be found at
http://www1.nasa.gov/centers/dryden/...ain_H-2510.pdf It looks like a fascinating read so I'll digest it at length later over a glass of vino.
A quick Google suggests that Concorde had a minimum approach speed of 160 kts however I'm sure there are plenty of ex Concorde drivers on this forum who can give the actual numbers.