If you have the ATP written and take a type ride in anything you will walk away with an ATP and a type rating. Just make sure you have the written first, and it is still current (two years). From what I have seen the standards for a type rating and an ATP are the same. Spend a weekend (and a few bucks) and knock out the written now. I have seen several guys that have gotten their ATP and type at the same time in courses that I have attended, (me included). It dosen't cost more, it's just additional paper work. It makes no difference if you do it in a light twin or a B747, it will still say ATP in the end.