Might be a little earlier than you wanted, but check out Muhammad ibn Mardanis, a.k.a. "El Rey Lobo," who ruled a significant piece of southeastern Spain in the 12th century. He was a "muladi," a Muslim of Iberian descent, who seized power as the Almoravid state collapsed. He controlled Valencia and Murcia, and briefly held Granada as well. While he himself was Muslim, his main enemies were the Almohads, and as such he allied with the Christian Iberian kingdoms, used Christian mercenaries, and entered into trade agreements with the Italian merchant republics. The kingdom was prosperous and exported ceramics, silk, and paper.
Militarily he was only mediocre. He made initial headway against the Almohads, and in 1165 he took Granada and marched on Cordoba, but was then heavily defeated by the Almohads. They raided the country, causing economic devastation and forcing Mardanis on the defensive until his eventual death, upon which his son pledged his allegiance to the Almohads.
A liberal Muladi king who is friendly to the Christian states, relies on Christian trade and soldiers, and is a sworn enemy of the Almohad zealots seems like as decent a POD as any for a "Mozarabic" kingdom, assuming his fortune is reversed in 1165 and his successors are of the same mind that he is.