In Max 2009, Spline Mapping was added to the UVWUnwrap modifier. However, once you have picked a spline in the uvwunwrap interface, changing the vertexes positions or changing the position / rotation / scale of your spline does not update the mapping. The modifier is not procedural, it's a one way process. This is problematic in a number of ways...

1) if you change your spline, you have to reselect your object, reselect the modifier, select face mode, click the Spline Map button and re-pick your spline (6 clicks)
2) You cannot see realtime updates in the viewport of your mapping, so when tweaking, you have to add an extra 2 or 3 clicks to the 6 clicks to reselect your spline and move the vertexes, which makes tweaking a very slow and cumbersome process.

I propose something closer to the spline mapping that exists inside of the TexLayers plugin.

Instead of updating the spline mapper in the UVWUnwrap modifier, update the UVWMapping modifier with a new mode called Spline.

And have a live link between your spline and the modifier so when you update your spline, you can see the results immediately in your viewport and final UVs without the need to repick the spline.

Go here for a UI mockup:

http://www.neilblevins.com/cg_tools/cg_wishlist/3dsmax/wishlist_splinemapping.htm