If you're looking at Ampeg and dont want valve, then you may be interested in my head i have for sale,
you mentioned the SVT450h, but i've got the SVT1000h, much better sounding amp, with loads more head room,
i play in a band competing against a 5150, and it cuts through, so much so that i have to run my volume on 3 or 4,
its clear, and has that great ampeg sound,
if you're interested then drop me a message,
cheers