I was told that Edraianthus do well here, and in my (albeit) brief experience with them, that seems to be true.
Edraianthus serbicus is a very showy one. Here's a plant in its second year from seed. Seeds were collected by M. Pavelka in the Konavska Hills, Bulgaria at 1400m elevation. Germination was straightforward and easy, with no seed treatment (e.g. stratification, scarification, GA-3) required; the seeds germinated at room temperature after about 10 days.
According to Graham Nicholls' Dwarf Campanulas (an excellent resource!), E. serbicus is endemic to a relatively restricted area of calcareous outcrops in western Bulgaria and eastern Serbia. Given its natural habitat on limestone substrates, my tufa bed (pictured) should be a fitting environment for it.
Its a very low-growing plant; even the flower stems in bloom stand no more than an inch or so above the ground surface. Here in this northern climate, the bloom occurs in late June and through July - a very nice addition to the rock garden, and probably a good choice for the beginner to try!