Blade II language: The price of conlanging

Well, this is just to announce that my association with "Blade
II" (the sequel to the Wesley Snipes movie of a couple years
back) has ended.  As you may recall, I was being tapped by the
makers of the sequel to revive the Vampire language from the
first "Blade" movie, which was originally designed by Vicki
Fromkin, a professor emerita in my department, now deceased.  As
it turns out, the producer and I were unable to come to an
agreement on the price, and so I suggested they find someone
else.

The whole thing has left me feeling very ambivalent.  I'll tell
you guys how I decided to proceed, and you can tell me if you
think I did the right thing or not:

Faced with the daunting task of putting a monetary price on a
conlanging project, I consulted some of my friends who are
self-employed in various arts- and entertainment-related
industries (e.g., graphic design), and who are thus used to
negotiating fees for creative work.  They advised me to treat
myself as a full-fledged professional/creative consultant, and to
charge accordingly.  After all, they reasoned, creating an
internally consistent language from scratch--and in such a way
that it matches the vampire dialogue from the original "Blade"
movie--is a highly developed skill, requiring considerable
expertise.  The fact that I have a PhD in Linguistics and years
of conlanging experience should count for *something*, they said.

So I thought long and hard about how much time and effort the
whole project would take, and what I what I considered the
'value' of the end product to be.  After much debate, I arrived
at a lump sum of $3,000.  I quoted my price to the producer and
she was, to say the least, dumbfounded--even outraged--at my
audacity:  She was expecting to pay no more than $500 for what
she assumed would be just a couple hours' work.  We haggled for a
bit, but once I realised that she was only prepared to go as high
as $1,000, I said no thank you.  And that was that.

Now I don't know what to think.  On the one hand, I'm proud of
myself for having stood my ground, and for having the
self-respect (as a linguist *and* as a conlang artist) to charge
what I thought my product was really worth, rather than what the
market would bear.  But on the other hand, I'm disappointed at
having thrown away the opportunity to see "Vampire dialogue
created by Dr. Matthew Pearson" in the closing credits of a major
Hollywood movie.  I'm also wondering if I wasn't being a wee bit
arrogant in asking quite so much for what was really only a few
hours of work (and very entertaining work at that).

So what do you guys think?  We all agree that conlanging is an
art, but was I right to charge as much as a portrait painter or
graphic artist might charge for a comparable amount of labour?
How do you put a price on conlangs, anyway?

Matt.