"What do you feel about the comparisons some people with BIID make between that and GID/transsexualism, and the connection some people make to Munchauser's Syndrome?"
The comparison with GID is definitely an interesting one on two levels, firstly because both conditions can cause an equal level of suffering and also have a disabling potential to them, in that the sufferer can become unable to function in life. I know of a great many people with GID who have at some point been unable to leave their own homes because they couldn't face the world at large due to their transsexuality and I hear occasional comments from BIID people that say pretty much the same thing.
The main reason BIID and GID are an interesting comparison is in the subject of how they manifest themselves. What's the effect of GID? A strong, possibly disabling, insistence that a person's physical sex is opposite to that of their mental sex; i.e. a condition where the brain tells you you're one thing and your body is another. What's the effect of BIID? A strong, possibly disabling insistence that a person's physical state is different to their mind's 'body image'; i.e. a condition where the brain tells you you're one thing and your body is another.
It's quite possible that they are entirely different disorders that give the same result but it's equally possible (because let's face it, there have been no decent studies of this condition) that they're the same condition manifesting in different ways. The comparison is therefore very interesting.
Munchausen Syndrome, however, is totally unrelated to BIID, in my opinion. I can see why some people would see a similarity but only in the same way as I can see why some people think transsexual people are just "gays who went too far"; i.e. they're ignorant and/or wanting to cause trouble.
In the case of Munchausen Syndrome a person feigns an illness or condition to get attention but someone with BIID emulates a condition in order to seek a release from the symptoms of their condition. I can't think of a single BIID sufferer who wants attention either, in fact the ones I've spoken to seek to be left alone while they go about their business. BIID people seem to have a massive hangup about being spotted and 'outed', so to speak, while emulating their desired condition.
So, in conclusion I'd say any connection with Munchausen Syndrome is a false one and could potentially be offensive, too.