Hi, Bob.
Believe it or not, I have one machine with Access 97, 2002, 2007 and 2010 all installed on the same machine. I use his machine regularly for development and update of all of the appropriate file types.
Mind you, I am not attempting to say that everyone should try this type of setup and I am quiet sure there there must be some reasoning behind what Microsoft has said.
All I know is that in the world in which is live and work, I still need all of these versions to do my work for clients. I still have situations where I need to open some old Access 97 database files and do some updates or even prepare them for conversion to some other version. I also have clients using 2002/2003, 2007 and now 2010. I would not want to have to maintain a computer for each of these versions so I have elected to keep these on the same machine. To me, there seems to be more of a difference between 2002 and 2007 than between 2007 and 2010. By this I mean, there is a delay between opening the 2002 version and the newer versions that seems to be more of a complete installation or change of components.
Bottom line for me is that I have no issues using all version on the same machine. The whole thing may blow up on me today or tomorrow, but up to this point I have had no issues.