on the typing more front words - have you seen tweetshrink? http://tweetshrink.com/ - it'll shorten words like later to l8r to save characters - http://tweetdeck.com have integrated it's api into their twitter client
Yep - looks very similar to what I've done, I hadn't seen it until a few days ago. We could do with even more similar services - to balance out the hundreds of url shrinking services.
Good point - what I've done is allow you to piggyback more than one lookup onto a single request. so the plugin will batch them in groups of 4. does that make sense?