no, more phone wouldn't make it faster
Also, having the hdd with you is really not required, you can just use a beefy external server you ssh to via a 3G data connection or something.
That article is just commercial BS ... the same way GSM pretended "Frequency Hopping" is a security feature because you can't listen to everything and don't know where to listen and you can't listen to everything without very $$$ equipement.
If CDMA is more secure (and I'm not saying it is), then it's not due to their modulation scheme ... it would be due to the better security scheme. (and again, I don't know their security scheme, so it may just be as bad as GSM)
Yes, 4 ... but the number is not really important, mostly depends on the activity of the cell. Also my code is currently highly sub obptimal (I use 1 entire phone to listent to 1 control channel ... in theory a single phone could dump 32 of them at once).
And only one single of those was modified (the one used to dump the traffic/voice channel, the other only listen to the BTS)