Thanks for the great ideas and tips!..
I have done some progress, this is what I have tried and it works perfectly...
I converted the a laptop to be its own hotspot by adding a second usb wireless adapter with its own SSID
- First, I connect to the VPN sending all traffic thru the first (internal) wireless connection.
- The wireless phone connects to the usb adapter's SSID, then I share the internet connection from the internal wireless.
- Phone connects and goes on line thru the VPN! - ok done.. (see figure 1)
On a second try I tested and probably simpler way.. was to just install Yate software (full installation that includes server and client - free software btw) - I got a google voice number and configure this software to use such number and connected a headset with mic to the laptop.
I connect to my VPN and then I can call and receive call just fine by sending all the traffic thru the vpn connection, - ok done (see figure 2)
All this works just fine as long as I have a good/reliable connection like Starbucks, coffee shop, etc... that I can use...
But, here is where the challenge comes, if I have no access to any of these places I want to be able to use a small unit (hotspot) from AT&T or T-Mobile (unlocked), get a a sim card from the local place and run a vpn thru this... I tested a ZTE mf61 T-Mobile 4g hotspot but the vpn wont complete(there is no handshake and it times out) - firewall at the unit is disabled btw so nothing internal on the unit that prevents the vpn handshake -, it seems like ports are blocked by T-Mobile even though the specs of the unit reads it has VPN support, called T-Mobile and they have no clue and unable to help... so I am not sure if this is a T-Mobile network thing or the actual unit (see Figure 2 for added hotspot possibility...).
Does anyone know of a hotspot unit that can be unlocked and accept vpn connections (IPSec/L2TP) - (pass through I would think)...? of course We would get this unit from eBay or some place like that w/o contract...