adj. Simultaneously skeptical and optimistic.
2011
Sen. John Lee, D-North Las Vegas, said he was "skeptimistic," both optimistic and skeptical, of any government plan that could bring back the construction industry.
2010
Well, if we collectively understood the imminent danger to our way of life, we might change. But history is full of examples that show people don’t change until disaster strikes. So who knows. Perhaps in this era of information and knowledge, we just might find the wisdom to shape a different historical outcome. Until then, I remain cautiously skeptimistic.
2005 (earliest)
Mark Twain is classically American. He’s energetic, skeptimistic (a word my wife invented), adventurous and boldly outspoken.
Urban Dictionary has a couple of earlier citations, one of which is defined oddly ("Unsure about a particular situation") and the other is just silly ("A state of being skeptical and pessimistic about anything relating to llamas or your mom").