I have an older UW housing that accepts any camera that takes LANC. I was using an older Sony Mini DV cam but it died. I can buy another one like it on eBay but I want to upgrade as far as I can.

What is the best quality video camera that I can use that...
1) can connect to LANC (L-Control) and
2) is smaller than 9'L x 5'W x 5'H

This housing uses only electronic controls. but has plenty of space inside to add some kind of adapter dangle if required.

Chris,
The higher end Canon camcorders have a lanc port. I think from the HFS20 up. They have quite a good picture on them & should fit your housing.
The other option is any of the Sony camcorders with the "multi" port. From this port, you can use an adaptor to go to the lanc connector on the housing. I have tried a few different Sony camcorders with the lanc protocol & did have one that wouldn't play nicely so there may be some trial and error involved.
Good luck!
Bryce

P.S.
Here is a link to a website you will find very helpful.
LANC Compatible Camcorders (http://www.aquatix.com/lanc_camcorders.htm)
Of course there are newer camcorders that are not on the list, but that should give you a good head start.