If you look at the tradeskill window just above the recipe list, you will see a text box with an EDIT button next to it. If you haven't created any filters, the box should say 'Unfiltered'. Click EDIT and you will get a dialog box that lets you set a name for your filter and select filter options. You can filter by level, skill used, recipe book, and target class. You can select ranges with SHIFT-CLICK and discontinuous items with CTRL-CLICK (standard Windows selection rules). Click OKAY when you're done, and your filter will be added to the list in the drop-down menu.
For the specific case you mentioned, you would select 'Paladin' in the 'usable by' list.
Filters are stored in the game program folder in a file called eq2_recipe_filters.vdl. In spite of the odd extension, this is a plain text file with simple XML commands to set your filters.
I use this feature a lot. :-)
The ability to search by a material type would be nice, but that would require changes by SOE. In the meantime, I recommend the 'Rare Usage Chart'
at EQ2Traders.com as a reference.
As for your other request, that would also require changes to the default UI by SOE.