Have some dedicated servers with PPtp`s & open-vpn`s
Need to control `em from 1 server with web-gui
generate certificates for open-vpn & generate links on server so users could download `em.
generate with time limitations/without for 1 user per account/multiple.
add/edit/delete users, control their balances,
take e-gold & webmoney as payment methods so you`ll need also to connect billing to my webmoney purse & e-gold account.
control tariffs add/edit/delete.