[zork]

I finshed my test and implemented a first version into my panel.

http://imgur.com/a/4WtBM

You can even freely resize the whole panel and the scrollFrame will be cropped properly. The scrollbar adjusts properly aswell. Very nice.

All what I had to do was:
http://code.google.com/p/rothui/sour.../subFrames.lua

If you are fine with the default template you can even go with

--create a scrollframe inside
    local scrollFrame = CreateFrame("ScrollFrame", "$parentScrollFrame", frame, "UIPanelScrollFrameTemplate")
    scrollFrame:SetPoint("TOPLEFT")
    scrollFrame:SetPoint("BOTTOMRIGHT",-22,0)
 
    local scrollChild = CreateFrame("Frame",nil,ScrollFrame)
    --scrollChild:SetWidth(scrollFrame:GetWidth()) --optional
    --fill scrollchild with data and adjust size
    genData(scrollChild,100)
    scrollFrame:SetScrollChild(scrollChild)