you can browse Tatiana tomatobase website for mmm, huge number of varieites LOL
If you anywhere close to North side of Chicago I host large plant swap during spring, several of my friends are usually growing a lot of tomato varieties to share and try, I am embarrassed to say how many do I have...LOL

I'm not familiar with Eva's Purple Ball but if you're looking for tomatoes on the smaller side I would highly recommend green zebras. They are highly prolific and the taste is amazing, not to mention it would add some nice color to your salsa.
Black Prince are prolific as well, but I can't say I was very impressed with the taste.
I grew Abe Lincolns for the first time this year and they did very well. Great flavor and they stayed fairly small.

It's Eva Purple Ball, not Eva's, I don't know who first put that apostrophe in there, it's wrong, but I first listed it in the SSE Yearbook in I think 1994 along with Joe Bratka, and EPB is a family heirloom of his and I know it well. One of the few heirlooms since he bred many varieties and passed them off as heirlooms, saying if folks wanted heirlooms, I'll breed them, and so he did.

There are lots of varieties about the size of EPB and here's just a few I would suggest>

Druzba
Jaunne Flamme
St Pierre
Earl of Edgecombe
Danko
Pervaya Lyubov
Break O Day

I don't know of a good medium sized Green When Ripe, most are larger, and I love GWRipes,

No sense growing any so called whites IMO since with few exceptions not great taste.'And while I;ve grown lots of so called blacks most are larger sized than EPB,

You can find all of the above and many more at Tania;s wonderful website, link below, with opinions from others, pictures, and seed sources as well.

Hope that helps,

Carolyn

Here is a link that might be useful: Tania's Website

I love to combine a red and an orange or yellow tomato for salsa, it looks so pretty, esp when you add in the green from the cilantro. KB is one of my favorites to do that with. I also like to use meatier tomatoes so the salsa is less watery and most hearts are good for that. Soooo many good tomatoes out there. I haven't grown EPB so I am not sure of its size. Sophies choice worked out well for me, also. It was recommended to me by Carolyn. It is determinate, early and smaller in size. Given your zone, like mine, early is good. :)

If your objective is salsa, Heidi is a good determinate for the purpose. Otherwise, Druzba and Lyuda's Mom's Red Ukraine are good general purpose tomatoes.

You might check at http://www.sandhillpreservation.com/

Pale Perfect Purple is like Eva Purple Ball and is very productive. I think Tania needs a better picture of it. In my garden it is more perfect than most tomatoes although I don't mind the irregular big beefsteaks. Wes is good for salsa because it is meaty but you want a medium sized tomato. Black and Brown Boar is a small black tomato - just the size to slice to put on a cracker.

Here is a link that might be useful: Pale Perfect Purple