Originally Posted by Nighttrain1127
It is going to cost you more to build the active Speaker and get it right than it would to buy a Small head and cab.
+1, and the amazing small amps out there right now are not much larger than some DI's! And, you won't need to worry about matching output/input gain with a preamp and amp that aren't designed to work together, etc. There are very few 'active' bass cabs on the market, and active PA cabs are usually pretty lame (i.e., woofers that aren't as heavy duty as in a good bass cab, and a horn that is not voiced very well for bass guitar, with no attenuator.
If you are convinced that for some reason you want to do this, Bag End makes their cabs with an internal power option. They are heavy, but should work fine for you.