Ratio of the thick disk scale length and scale height as function of circular velocity, v_cir, for five of our dissipative/dissipationless and single/double minor merger models, as well as for two unstable gas-rich clump disk models (gSb+u1 and gSb+u2, see Fig. 6 for the notations). Also shown are observations of a sample of late-type galaxies from Yoachim & Dalcanton (2005) (open and filled circles) and of the thin and old thick disk of the Milky Way (Larsen & Humphreys 2003).