Hi !
Why not use FLstudio as VSTI ? Then you could keep slicex inside FL.. (and so much more!)
or you could get slicex as VSTi too ...
I too tend to use Dropzone for quick and dirty substitute to FL ... but it just does not cut it,
except for very simple sounds.. like hand claps...
I would suggest Xfer Nerve, although it's a little expensive, especially compared to FL...
http://www.xferrecords.com/products/nerve cheaper than that, you could get a second-hand copy of Ableton live (kvraudio.com's marketplace is a great start), and use it via rewire (slice to MIDI pads is instant, working great), keep in mind that Live INTRO does not allow you to slice WAV's... you need the full version, or live suite. AND you need the x64 version (beta), on ableton's site so it works in Sonar. (and it does wonderfully)
Hope this helps !
Cheers !
V