I confirmed with MacWarehouse (two weeks ago) that one can get a 7.1 upgrade kit without any restrictions and then qualify for the 7.5 upgrade. The only problems, which may be fixed by now, were that the floppy version of 7.5 was not in stock and that they didn’t have or know about a CD version. A quick comparison showed that this is not a bad deal ($80.90) even compared to the user group special ($64.90), and it may involve a shorter wait.
The deal improves for people wanting to upgrade Now Utilities as well. A new copy of Now Utilities can be had for $29.95 from MacWarehouse with 7.5 (no additional shipping) versus $39.95 plus shipping from Now Software directly.