Well you already know that I have one and love her.
Most will stay in the 5-7 foot range but the largest females can get up to 9 (though 9 footers aren't all that common)
And thanks Mike I've yet to find any info saying that there are any known morphs. I have yet to see a Dumeril's that I thought looked bad...
The best thing about Dumeril's is that they are so calm. I could do just about anything to my girl and she won't react. She moves around and is interesting but does so in a cautious way that is easy to handle.