[dice]

Pay attention to the names, too.

Black Cherry: sounds sweet
Sunsugar: ditto, although not as cool a name
Sungold: sounds golden
Box Car Willie: "Hobos know what to pinch."
Brandywine: what does that sound like to you?
Cherokee Purple: sounds interestingly rustic
Pineapple: sounds sweet and gigantic
Aunt Ginny's Purple: sounds like rural wisdom preserved
across the generations
Redfield Beauty: sounds like it produces "perfect tomatoes"
Pale Perfect Purple: ditto

And so on.

You have to balance this, of course, against the actual
tomato and how it will grow in your climate. No good
seducing someone once with a fancy cultivar name
only to have it produce very few or extremely bland
tomatoes that make them wonder why they bothered.

The fact that "purple" anything is usually pink
may put some people off that aren't expecting it.
It may help to put the purples in either a "pink" or
"dark-fruited" section (Aunt Ginny's vs Cherokee
Purple, for example), so it isn't quite as much
of a surprise what color the ripe fruit are.

Counterexamples:

Earl's Faux: terrible name for marketing. The "Earl's"
part is ok, the "Faux" is too obscure sounding.
Only cognoscenti who have heard of it will
buy these (so don't sprout very many of them
at first, until word gets around, since you might
end up growing them all yourself or donating
them to a 4-H group or something).

Something like "Earl's Hot Pink", now that would sell
anywhere.

PS:

Although the name is not very flashy,
Stupice does well in your area (according
to Carla, who posts on GW). It is early, and
it survives the heat of mid-summer, producing
small, tasty tomatoes over a very long season.
Eva Purple Ball is more interesting sounding,
and it is rumored to do very well in the heat, too.

Edit:

"Sungold: sounds golden" (imagine what you
thought the first time you saw golden figs or
golden raisins for sale somewhere).