I'd say the problems lie in your definitions, as...well, really, I can't find anything that supports a definition of faith as "Belief in something one cannot observe or reasonably conclude."
According to Merriam Webster, faith is merely "firm belief in something for which there is no proof," with other dictionaries having similar definitions. In other words, faith extends to anything that you cannot demonstrate beyond a shadow of a doubt. I have faith, for instance (totally hypothetical, no one try to use this on the NFL thread), that Kansas City will win tomorrow's playoff game. I have plenty of reasons as to why I think this, such as Houston generally sucking and KC's defense being set up almost specifically to foil Houston's offense. I am quite confident in KC winning, and I would argue it's a very reasonable belief, but in the end, it is still something I cannot prove, therefore it is faith.
So, no, faith does not imply a lack of reasonability. Certain beliefs that you may have faith in might be unreasonable, but as a whole concept, no.
EDIT: As a side note, if you leave the definition faith as is, then there's hardly a debate to be had, as you've simply created a tautology. Reasonability requires...well, reason, and if faith is, by definition, absent of reason, then obviously it must be unreasonable.
