As promised, we figured out a way to get the Merlin S720 working on on PowerBooks with a PCMCIA slot (sorry, MacBook Pros have an ExpressCard and Sprint doesn't have an ExpressCard solution - they do have an EVDO USB Solution).
Over the last 2 years, we have always figured out a way to allow all the Verizon and Sprint cards to work on Macs. The Merlin S720 was introduced last week and it doesn't work with Macs without hacking it first. It isn't supported in Mac OS X 10.4.7, but with a simple modification to Mac OS X 10.4.7, we have a way to get the card working.
It is important to know that the Merlin S720 needs to be pre-activated in a Windows PC before it will work on a PowerBook. As a service, we can activate the Merlin S720 before sending it to you if you do not have access to a Windows PC (option on our order form).
The hack involves modifying Mac OS X 10.4.7 so that it recognizes the Novatel card. We basically modify the Novatel 620 settings to recognize the Novatel S720 card. Once this simple hack is completed, you will NOT see signal strength, BUT you can connect from your PowerBook.
Here are the directions:
Merlin S720 Hack For PowerBook