Im looking for vps that's suitable for running openvpn. preferably tun/tap enabled by default. preferably someone who can offer me trial server for me to test the openvpn on your vps. Please also tell me how many connected clients can your vps handle per each server. thanks!
Hostome.com might able to help you with this and offer account for test period, so you would want contact sales and check
Most if not all providers will allow VPN's on their VPS's, TUN/TAP module may not be enabled by default for every VPS but likely you can request it from them when its not. Not very many providers allow trials of their VPS's, you may find some promotional offers on some forums allowing a trial of the services, but then you'll be limited by the hosts offering the trials, and not necessarily on the quality of the providers.
Sibername.com provides many VPS deals which are not pricey and rich in resources. Concat them to get to know more info about their services. Active and responsive support they have.