OK, let's get some stress testing going, shall we?
This test took ABSOLUTELY AGES to get working, because my Mac and iPod suddenly decided they were no longer friends, and XCode was playing up like a moron.
AN HOUR!!
For two little bloody tests.

rediculous!

However, what we have here is code that I wrote on a PC, tested on a PC under HTML conditions, then ran on an iPod having compiled it under reasonably fast conditions. (*aside from the bitchyness of the device!)

-=-=-

Here's the results..

Left = 100 sprites onscreen, Right = 330

If you try bumping it up any further than that, it'll experience slowdown, and the framerate plummets.
The difference between the two shots is the sizes of the sprites used.
On the left, the sprites are a whopping 640x640 pixels.
On the right, they're a more moderate 64x64.

This is running on the newer iPod, the one with the new-tall retina display, which I think is 4th gen, although it may be 5th.. can't remember.. not keeping up, to be honest!!

So, anyway, if you're coding with Monkey, that's roughly what you should be expecting to get.
If you're using WAY too big sprites, you can still manage to get 100 onscreen at once. To be honest, I wasn't expecting it to be that good! It's surprised me.
Given that result, I was expecting huge numbers for my smaller sprites, but alas, that wasn't to be.
Still, can't grumble.
300 little sprites is PLENTY, and you can get all kinds of neat little tricks going, especially given that that includes scaling, alpha transparency and rotation, too!

Stress Test is over.
Next up, I gotta get some proper bitmap fonts working, I think..
ugh..