Fetches, caches, and displays current cryptocurrency prices (bitcoin and litecoin, for now).
Yes, simply modify the included crypto-ticker.css file, located in the plugin's /css directory.
You can preview the look of the plugin on http://www.cryptobadger.com .
I may add the smaller altcoins in the future if there is enough interest. If you can't wait, adding them yourself should be a trivial task; just keep in mind that because of the way the btc-e API is set up, each additional currency means an additional request, which will impact performance on cache misses. If I do decide to add the other altcoins, I'll probably re-write the widget so that the requests are asynchronous.
Not at the moment. If there is enough interest I'll add other currencies later.
Try temporarily disabling any other WordPress caching plugins that you're running, and then delete my plugin's cache from the options menu. If that doesn't work, ensure that outbound traffic on port 443 (SSL/HTTPS) is open from your server - the plugin fetches quotes on that port.