To be very honest with you - as a breeder - I don't see what is so bad about $100 for a chocolate otter holland lop. I paid close to that for my chocolate doe to breed with my broken black otter buck - and I got a chocolate otter buck.
I think you need to remember - some breeders are what I would call "hobby" breeders - they're putting together bunnies and making some money and they aren't looking for particular colors. So they're maybe willing to sell their rabbits for lower prices.
Then there are breeders that specialize more in "show quality" rabbits - even though they are breeding as a hobby. They base their breeding choices on what they think will produce the best rabbit for show - not so much about color - but about the quality of the rabbit for body type, etc. These breeders will definitely charge more - odds are good they've been breeding longer - have a good reputation and good bloodlines. $100 isn't bad if you're talking about a show quality rabbit.
Something else to consider is that while a color may be "rare" in one area of the country....it may not be rare in another area of the country. For instance, when I was wanting to get into black otter lionheads - I was told they are a dime a dozen (not literally) up in Minnesota. Here in TX? Very rare....
I don't remember if you are the person who posted in the general forum about debating between a fawn holland lop and a chocolate otter holland lop. I wanted to post there - but held myself back. However, since this is the rabbitry area, I'm going to speak from the perspective of a breeder.
Whenever I have people tell me they want a certain color - I always told them that they would have to come see the rabbits. I sent them pictures and descriptions of more than just that one color....and I rarely ever sold a rabbit without watching a person interact with the rabbit.
There is so much more to a rabbit other than color and the personality of the rabbit has to be a match for the person that is wanting it. If a person is wanting a rabbit just for show (vs. a pet rabbit) - I'm less likely to turn down a sale....but if they're wanting a pet rabbit - I've been known to tell them "no" because I did not feel it was a match for them. I'd watch the rabbit interact with them and if the rabbit was uncomfortable....it wasn't going to their home no matter what they paid me. And yes - I've charged $150 for a high quality show rabbit...and got it. The people drove 8 hours (one way) to get him...and another rabbit too. They knew all of the rabbits I had for sale and they took two hours to play with them before they made their choices. Would I have let that rabbit go to them if he didn't like them? Nope - wouldn't have matter that they wanted that color or not. To me - as a breeder - the rabbit comes first....
Good luck in finding a chocolate otter - I wound up giving mine away to a woman who wanted a holland lop very very badly and she fell in love with him and he fell in love with her. In fact, here he is. (I very much wanted a chocolate otter girl and he was a boy...)