After reviewing this with another person from our fine community it was suggested I post these websites I found. These sites allow you to find colors closely matching in just about any paint line available...these 2 links work in conjunction with each other.

Color Match
Color Chart

I was looking or a cool Merlot red color for my Chaos Marines and dug this all up. I went to the Color Chart and found the red/purple I liked (#770033) on the chart. Then you plug that number in the Color Match program.

1. Click RGB Color Search
2. I picked Vallejo Game Color
3. Hex RGB Input = 770033 <---no # sign
4 Color Range = 50
5 Paint Type = Water Based Acrylics
6. Finish = Flat
7. Lines to Search = Just left all unchecked

And it drops a nice swatch of your color and all close matching from other ranges.

Two others form same site...
Color Shader
Paint Line Match