Proxy Setup mit 4g USB Dongles (linux?)

Ich habe die Beschreibung vorerst auf Englisch verfasst: I'm looking for somebody to set up a squid/open VPN/other proxy solution on a Raspberry pi 3. The machine is on my local WLAN, and it has both a wireless connection and several USB dongles for 4g connection. I would like to proxy via this machine using the IP and then connect to internet via 4g. It has to be anonymous (should not be detected as proxy), reliable and easy to use (i.e. I can proxy into it using ip:port1 for usb dongle 1, ip:port2 for dongle 2 etc.). I want to be able to proxy via any computer into this one, and have my public IP show as a 3g/4g IP from the USB dongle. I will give you access via SSH, and you'll get paid for the gig immediately once the setup is working.