ACTi has an E46 camera which is supposed to be an excellent low-light performer, however, I cannot seem to find any video of screenshots from it. Perhaps that might be the option. I do like ACTi's NVR software, and like you said, the daylight quality is exceptional, and their price isn't bad at all.
I found the E46 for $506 on a website, so price wise it isn't bad, IMHO.
I might try getting an additional IR panel to see if that helps.