From the Twins system, there are 2 prospects that were in low-A or rk ball that could start gaining attention in the next year or two. They're both a long ways from the majors and now are mostly toolsy. Not sure if it's exactly what you're looking for.
Wilson Ramos - C - Could develop into a top catching prospect in the next year or two.http://www.thebaseballcube.com/players/ ... amos.shtml
Deibenson Romero - 3B - Has all of the tools to develop into a very good 3B for the Twins.http://www.thebaseballcube.com/players/ ... mero.shtml
I'm guessing that both of these guys are outside of the top-250 lists (if someone put out that list) and could easily bust, but they have the tools to be above average MLB'ers. I've left out 1st and 2nd round picks like Revere and Benson. The Twins also have alot of promising arms in the minors, but other than Guerra, none of them have shown front of the rotation potential. Hopefully someone breaks out this year.