I've been wondering this as well. Or YAML. Parsing large amounts of XML seem to take a long time. ie. I have about 300 movies in my home stream, with minimal info in each node, and it takes it about 3 seconds to parse. The videoplayer example also appears to re-parse when you select an individual movie but that's just a app design issue (ie. the server should be dynamic instead of static files like I am currently using and only serve up the title's detailed info at that time).
I also see in the XML a mention of pages, but haven't seen any examples of this being used. eg. breaking the list up into chunks and only serving up what is needed for several screens worth.
I would think that a list of 300 movies is more than you could display on screen. You could implement a search screen and capture screen events (roMessagePort) to determine when to get the next or previous "page" search results. You could also just display the movies alphabetically, 10 or so at a time. I would think that parsing more than 10 results at a time is just wasted effort.
From another thread...
Check out the feedPagable.brs in the youtube application for an example on how you'd do this type of processing.
Keep us posted... I'm curious to see what you come up with.