I was looking for something like you are asking about in question (b). You may like to look at Thurallor's SequenceBars
Although it does a LOT more than what you need. The demo video
shows an example of using SequenceBars to swap out ALL equipped items (the example is switching from Tanking to DPS and back again). Obviously you can customize any swaps like that for any equipment slot. The items replaced are put into set Inventory slots which are kept the same despite the odd way in which LOTRO inventory slots IDs get jumbled when the inventory is re-arranged so you don't end up losing track of your alternative equipment items.
I've only just loaded it so I can't give a personal testimonial but it certainly looks like it solves many of my problems.
Hope this helps.