AFAIK a "large" dealership that may _already_ have an Insight in its allocation could be "faster". But once your in the system you'll get one.
The problem right now is production. As you are aware Honda has only manufactured the Insight in limited production "runs" for the last couple of years, the first of 05 already being sold out. There are rumors that Honda is planning a second run. I guess you'll find out if you try to order one :!:
The 06 model Civic is _rumored_ to have a next generation engine available that even without the hybrid system will approach 60 MPG.
If you can wait maybe its best to revisit your purchase decision in late August when the scoop will be available on this new model. On the other hand if its doesn't turn out to be what you would want you may miss the opportunity to purchase an 05 Insight permanently. And as we all know the rumors persist that this will be the last year of the Insight.