SWR Baby Baby Blue + Markbass1x12''cabinet + wich poweramp???

it all depends upon your budget, how much weight you're willing to carry, how loud you want to be, and how upgradeable you want the poweramp to be.

I would seriously reccomend no bigger than a 2 space poweramp and putting it in a 2 space skb or gator type rack case. As I've mentioned before, i use a stewart 2.1 (the brand really isn't the issue here) with the head only version of the the baby blue. I have the poweramp in a 2 space skb rack and it is super portable. I've used the amp with other preamps, heads, and cabinets, and having it in a small rack makes it a snap to use with anything with a minimum of hassle.

You may want to look around for a used poweramp. maybe try the talkbasss classifieds.