If you need a sat phone I would second Cascade Outfitters. Call them and talk to them about it, they are really great guys and gals down there.
On the side of the SPOT - I have used the SPOT extensively to include flying flying out a fellow rafter out of the MFS a couple years ago utilizing the 911 function.
I use the check-in function every day that Im in the back country. This way if something happened that I cant get to the SPOT to send out a help there is a last known place to start looking.
IF YOU USE THE SPOT PLEASE READ THE FOLLOWING-
Go into your profile and fill out the emergency information. Tell them you will be on the river and that you do not need a ground search and rescue team if you are using the 911 function. I talked to them after the incident on the MFS and was told they were not sure what to do until they read my profile and figured out that we needed a helicopter. Put in your profile that you need a helicopter if you use 911, nothing else.
Just my .02