For whats its worth, stay away from the combo's, I had a combo Thunder and it was ok, but it didn't sound nearly as good as the head + Engl cab version that I played afterwards, the definition and low-end just isn't there with the open-backed combo. I now have a Fireball head that I got for £500 with footswitch included off eBay, and then I bought the Framus V30 cab from Thomann for £200 = £700 compared to the £1500 that you were quoting. You need to search a bit harder, that price is wayyy off! :P If it helps, screw the Engl footswitch and just buy the latching Boss FS-2 instead which is cheaper. Saying all that though, if you can get an Engl cab it is definitely better than the Framus. eBay is your friend for Engl stuff.
EDIT: In response to the above about Engl cabs, they are great at what they do: Modern Metal, clean, mega-tight and almost sterile, which I love but its not really a vintage-sounding cab!