So are these cards still rebadged NEC 720101 USB cards with a modified PCI ID? (They sell for $7 or so)
?
Yes, thats right.
Does this mean that any USB card using the NEC 720101 chipset will work? If so, I found USB cards with this chipset for even less at $4.98!
Yes, with an different subsystem id. I see you have no signature, I do however.

How do they change the PCI ID of the card? Jumper a few pins on the ASIC? Can someone mod their own $4 board so as to not require software patches??
Atc24lc02 can easily be programmed, yes you can mod your own.
@alexh
perhaps they reflash the small 8KB flash or eeprom chip. Depending on the chip model perhaps they update it using software (like uniflash) and they don´t need to modify anything of the hardware.
They did remove the atc, programmed it and soldered it back on, looks like they didn't have a test clip for easy programming.
But yes you can reflash it. I like .5... instead of .5..3
We have banks and politicians to do that, no need for us to join in.
I'm a bit shocked to see some of the comments here to be honest. It's all well and good giving Elbox a hard time (and no, I am not in any way defending them), but surely with the wealth of coding skills among A.org members someone here could write a generic driver themselves rather than saying it's what Elbox "should" have done.
Why do it so difficult, serial eproms are easy to work with.
There are several low cost solutions for flashing 24 series, look on ebay. You can build a programmer for less then 20$.