Hello!
You sound like you're looking for exactly what I have been using for the past year.
I bought (about three years ago) a Sony DCR-HC1000. It is only available through eBay now. It is a 3 CCD Mini DV system. The pictures are awesome IMHO. It also has 3 CCDs which are used to record the light in the three main colors and electronically "re-assemble" them to the tape. Colors are wonderful.
For the past year, I've been using an Amphibico Invader VHIS 1000 housing. It's no longer in production (Amphibico is good about supporting discontinued products). There is a review here:
Amphibico Invader Video Housing Review - digideep.com :: list of all underwater housings suitable for digital photography and videography...
You might find one on eBay.
Retail the camera was 1200 and the housing last sold for 1500.
I started out with lights (2) and, like you, I wanted to film in mostly shallow waters 40-60 feet. So I've quit using the lights and have had good results. The interface with the camera is an electrical (LAN C) connection. You have control of all the important functions - ESPECIALLY white balance! The housing also has a flip down internal "red" filter if you choose not to white balance. It also has a 120 degree wide angle dome port which is great for most shots. If you are wanting to do macro (little critters), you'd need to get a different port.
I absolutely love my setup. It's small and takes great images. I've not run into any issues with low light. I have very little desire to upgrade to HD. I've been interested in doing that, but after reading many threads here, I really don't see the benefit especially versus the COST$$$$$.
Just my very biased opinion.
Good luck.
Kent