Zinn, one manufacturer that readily comes to mind, does 130-220mm for reference - these are custom, apart from the mass produced crankset lengths.
Expensive and painful are relative terms; I can acknowledge that. But definitely, switching cranksets in and out doesn't have to be either or both. Ebay can be your friend (new 105 cranks for $30-40/set), and once you notice a twinge, you stop (obviously) before something becomes painful. 5mm either way should not cause any pain unless your seat height is totally out-of-whack.
If trial-and-error seems beyond your abilities, then by all means, get fitted by a pro who should take aforementioned measurements...