I've taken a different tack now. Since Android has a built in RTSP client already, I'm using ffmpeg on a remote machine to transcode the FLV to an MP4 that Android can play. This is fed to a DarwinStreamingServer and I just use Meridian to play it.
Now that ffmpeg supports rtmpdump's library, ffmpeg can do all the work in one shot. I've attached the perl script I use to grab a H,u,l,u stream and republish it on the server. ffmpeg grabs the stream using rtmp and re-encodes it and pushes it to DSS. Once the encoding begins you can use Meridian to open the rtsp URL.
T-Mobile's 3G network seems to handle a 400-500kbit/sec stream here in Los Angeles, but it's not consistent. Sometimes it hits a glitch and doesn't recover, sometimes the audio continues but the video stream gets lost and doesn't come back. So probably it's safer to use a smaller bit rate.
Note that H,u,l,u uses 3 different CDNs - Akamai, Level3, and Limeworks. Currently this script doesn't support Limeworks. Basically what it does is grab the lowest bitrate H264 stream from H,u,l,u (usually a 400kbps 512x288 stream) and re-encode it to 480x270. To use it, just run "h,u,l,u,p,u,b <h,u,l,u URL>". You'll need a recent SVN version of ffmpeg built with --enable-librtmp to be able to use it. And of course you'll also need DarwinStreamingServer. I haven't been able to make ffserver work yet.
If you're connected on a decent network with wifi you should have no trouble playing the full 400-500kbit rates. On 3G you might want to stick to 200 or so.
I haven't figured out where to go next with this. Right now I'm thinking about modifying this script so it can be run as a CGI. Then you just use the web browser to navigate the h,u,l,u web site in one window; when you get to a program you want you copy its link and paste it into a form on another window that invokes this script and returns an rtsp link as the result. Then click on the rtsp link and the media player will open it.