I haven't done it yet but if I were I would just be running it with Celetion equipped MB Thiele cabs. They has a nice warmth that I love.
After I posted regarding the cube I figured I would search ebay, craigslist and even GC used online and my decision was to pass on it. I have done this search many times and have never been convinced to go this route. So I am still in inner debate and conflict.
This website added fuel to the fire as well:
Lots of choices and deviations to choose from. The best mental choice that I may consider is to build another amp with a higher powered back end to improve headroom and no master.