Cant be done, not in the way you want (because you cant do thsi with a node just a tool). Dont be afraid of many nodes, things dont get better with less nodes around they get worse.
Maya has handles for those attributes for the viewport, inform of a tool tough, but alas you need to switch the tool on by selecting show manipulator tool*. If you select a spotlight when you have a show manipulator tool selected you get to adjust all of these in the viewport.
Incidentaly it has handles for:
position, aim, rotate pvot along aim, cone angle, penumbra angle, start distances for fallofs 1 2 3 and all barndoor settings (in look tough viewpiort views)
but i would find it ideal to have all those controls encapsulated under one node parented to the light.
What you really want is a tool. Anyway you dont really need this one its builtin**.
Now only do this if your aim is to change the way this tool works. If not then you cant really make nodes that have manuy different tools that work well without actually using the show manipulator tool options. Anyway linking the tool with your existing node is a bit painfull and you really dont get any advatage of using 1 supernode for many things, in fact it gets inferior.
One of the key things to do when getting into development is to know what you have first, only then can you go forward. Its very easy to develop thinsg that maya allready has. Even autodesk does this constantly, because they dont know what they have. Be carefull of not joining the crowd.***
Are there any examples out there that could help get me started?
yeah footprint locator and footprint manipulator nodes. NOt that tahy really take you furter in the way youd like if you disliked the default tool your not going to be much better with this info alone.
- Which is under utilized, you NEVER see rigs that are designed to use show manipulator tool. Even tough youd get rigs that much better isntatly if you did. Because msot users NEVER use that functionality.
** if you did know what that this one existed then what is wrong with the tool? The defualt setting?
*** best use of maya api is no use.
PS: if you really want to do this then start of by makeing teh exact same tool as maya has but wuth different cycle order tahat retains order.