Congrats on the trailer!!
It is funny 3 of the 4 issues you had I had a problem with too!
1. That TV is garbage! On our first trip we ended up driving into a nearby town to a Walmart and bought a 19" flat screen they had on sale and have never looked back.
2. Ours didn't come with electric jacks, but the crank style ones on it are pretty low budget jobs! I had to replace the "A" frame jack at the front of the trailer after the gears stripped on it, we replaced it with a much better unit.
3. no problems with the AC or Electrical, so I am knocking on wood with that one!
4. The Stereo/CD/Surround Sound unit that came in ours looks like it was made by the same people who made the TV. That thing was horrible! I ended up replacing it with a Panasonic Automotive head unit that has CD/Ipod-Interface/Aux capabilities, hooked to a pioneer amp and new Polk Audio 4" speakers in the ceiling and Polk Audio 6X9's speakers in small cabinets. Also purchased a Sony Blu-Ray player and run the audio through the Panasonic "Aux" input, and it sounds pretty good.
Sounds like you have customized it pretty good! Have you "DeBadged" you trailer yet?