We have had a good experience with Laurel Springs, esp the textbook courses, which are produced in-house. Their in-house online courses are great, but beware the online courses they buy from Apex or other vendors(Multi-choice, machine graded ugh!!) The textbook French is serious and well done. We hated the online Middlebury/Powerspeak option they offer.

They are very good about acceleration and very experienced with it. They will customize courses (eg adding more novels and essays).