Podcast icons: what's available

UPDATE: check web.forret.com podcast feed buttons

I am looking for a good Podcast logo, something as slick as the AntiPixel buttons for RSS feeds.
I actually would like to see a logo that has the acronym ‘MP3’ in it, because I think there will be podcasts with MP3, with AAC, RealAudio, WMA, … audio files. Even if these formats are not yet supported by most devices, they do work on a PC. Subscribing to a RealAudio podcast feed is an easy way to get all the latest songs/mixes (e.g. backroomsounds.blogspot.com) automatically downloaded into a folder where RealPlayer can pick them up next time it starts. As universal as MP3 may be, it does not deliver the same sound quality at 32 kbps as RealAudio or WMA, and if one has to choose between delivering 15MB RM files or 30MB MP3 files, bandwidth pricing might come into play.
There is a discussion on whether podcasts that use BitTorrent should have 2 separate feeds or include both links in 1 feed. Personally, I prefer the latter scenario (let the aggregator decide what it supports/prefers). So I don’t see the need for making clear in the feed icon that the feed includes bittorrent or not.