Voxengo's free "Boogex"-Guitarampsim-PlugIn does allow to use just its Cabinet impulses if you turn the "Dry Pre Cab" knob to zero dB and the Amplifier Output down.
http://www.voxengo.com/product/boogex/
Combined with the Wagner Preamp: goodness

I was going for a darker sound.
Four tracks of rhythm guitar, after four bars the bass kicks in, the last four bars there's a little solo (of course also courtesy of the wagner-plugin), spiced up with a cubase's mod delay.
http://www.serotone.de/mp3s/wagner test with voxengo speakersim.mp3
All the best!