I need an OpenVPN, L2TP, or PPTP client for Linux - don't care which - that acts as a SOCKS5 server on the local machine. It should not set up tunnel interfaces or anything like that, it should just bind a specified port and talk SOCKS5 on that port, and forward only proxied traffic over the VPN. Ideally, it should not require root privileges to run.
(This is essentially the same question as OpenVPN client as SOCKS 5 server? , except that that question is for Windows, and never got any actual answer.)
(I want this because I'm going to be running several different programs simultaneously on the same machine, each of which needs to talk to a different VPN server; this is trivial with SOCKS, but setting it up with TUN/TAP interfaces looks like a giant pain in the butt.)
(Note that as far as I can tell, 'socks-proxy' mode in OpenVPN is exactly the opposite of what I want: it still exposes itself as a TUN/TAP interface to the local machine, and connects via SOCKS to its server.)