Anyone know the current status/location of the 'Smart Part' web part
download files?

It used to exist here:

http://workspaces.gotdotnet.com/smartpart

But, as you can see, one gets redirected to a 'The GotDotNet site is
being phased out' message instead.

It appears that this is the 'home' of the smart part now:

http://www.smartpart.info/default.aspx

But, it, too, points at the same dead link above.