Then VICIDIAL is definitely for you!

VICIDIAL works with most softphones, including XLite and fully supports remote agents, both inbound and outbound...... that is if you have enough bandwidth for those calls. Remember, VICIDIAL is built upon Asterisk, and also Trixbox. That means the same options could be built in but they have different directions.
I agree with you...... Trixbox is not really meant for an outbound call center environment........It is great though for inbound and if you have little or no knowledge of Asterisk. I have been following Trixbox for the same reason until I stumbled upon VICIDIAL.
Don't get me wrong, I am not knocking Trixbox or Elastix, a similar distro to Trixbox, at all. It is all about what you need for your business. I have to give Elastix credit because they have built a wonderful "campaign builder" tool but although they "advertise" it as a predictive dialer it is at most an autodialer and there are almost zero support in the forums.
VICIDIAL however have all the needed functionality and one of the most supportive and responsive forums around. No, I am not affiliated to VICIDIAL in any way........... just giving a couple observations.
I am sure VICIDIAL can offer ALL that you need, but then you have to prepare yourself to do some manual configurations, which is probably a good thing because then you will understand the whole Asterisk "thing" better.