Not exactly a VST multi but I think it belongs here anyway.
Here is a track template I put together for a bit of fun and it works very well for me.
https://stash.reaper.fm/v/949/Fruit%2...RTrackTemplate
It Rewires a folder of 12 midi tracks to FL Studio, you could have 16 but that would be extravagant ;-)
The folder tracks are for writing your midi parts in to send to FL channels. The faders don't work because the are not recieving any audio so to write any level changes you have to use a volume Pre FX envelope, or you could use FL Studio automation too I guess.
The resulting audio comes back through the end of folder track where you can record it into your Reaper project. There are a lot of good synths and sounds in FL Studio and 12 tracks of fruity synths uses only about as much as cpu as 2.5 VSTi's on my set up, so it makes sense to me.
For noobies
On my system it goes here:
C:\Documents and Settings\Kev\Application Data\REAPER\TrackTemplates
Also: To open folders simply click on the top left button next to "FRUIT FOLDER"
Any questions please ask, and if anyone knows how to make midi track faders work in Reaper could they also let me know.
Hope somebody finds this useful.
You can download FL Studio 8 here:
http://www.flstudio.com/documents/146.html