The sentence "There is a such difference" is correct and usable in written English.
You could use it to show that there is a significant distinction between two things. For example, "There is a such difference between eating home-cooked meals and eating out every night."
The structure of a difference dilemma is this: there is a difference, such as that only women become pregnant or that an employer has a history of refusing to promote women.
There is a difference between such truths as are merely of a speculative nature and such as are allied with practice and moral feeling.
There is a difference between such spending and being a shopaholic, chronically throwing money away.
"There is a substantial difference between such deliberate attacks against civilians and children and unintentional strikes against civilians that are part of legitimate actions to fight terrorism.
Growth rate and behavior may be difficult to quantify in the field or from routine surveys, but there is a possibility that such differences are correlated with physiological characteristics.
There is a vast difference between gathering in such numbers to protest something deemed politically unacceptable and burning cars after the loss of a hockey game.
However, the really smoke flavored wines are due to the fact that the wines have been fermented in barrels that have been deliberately "burnt", such that there is a distinct difference between these two styles of Pouilly Fumé.
But there is a notable difference in the usefulness of such listings that come up.
There is a big difference, and yet one sees such ambivalent statements all the time.
But there is a world of difference between such abstract knowledge, and the first heart-stopping sight of it.
But he adds: "There is a difference between talking about such a tax regime and committing to the finer details".
