The main concern I had with buying one of these is the lack of Analog support. Lots of reviews I've read say that when you use the connection you loose remote control over the dock. Can anyone confirm that remote control is not lost when using the adapter with a 30-pin universal dock?
I believe there are adapters that will fit the new ipod into old docks. Try this link
I have this adapter that I use with to connect my iPhone to my clock radio for charging purposes: http://store.apple.com/us/product/MD824ZM/A/lightning-to-30-pin-adapter-02-m?fnode=45
Same basic thing as the other poster linked to, except it has about a 6 inch cord between the ends. I did not trust the short stubby adapter to support my iPhone when connected to the dock connector on my clock radio. With this adapter, I can just lay the iPhone across the top of the clock radio while it is connected.
I did test playing music with my iPhone while connected to the clock radio with this adapter and then tried controlling it with the remote. It worked fine for me.
The other option would be some sort of Bluetooth remote to control the iPod and just using the head phone port. You could then connect the iPod to basically any set of computer speakers or some full audio system (i.e. receiver/amp with a head phone jack in that connects to "normal" stereo speakers) and control the iPod with the Bluetooth remote. Here are some options, but I am sure there are others:http://www.amazon.com/Square-Jellyfish-Bluetooth-Samsung-Android/dp/B00K6ZTDNO/ref=sr_1_8?ie=UTF8&qid=1403627384&sr=8-8&keywords=bluetooth+remotehttp://www.amazon.com/Satechi-MediaRemote-Bluetooth-Multi-Media-Control/dp/B00824948U/ref=sr_1_1?ie=UTF8&qid=1403627609&sr=8-1&keywords=bluetooth+remotehttp://www.amazon.com/Scosche-controlFREQ-Bluetooth-Wireless-Control/dp/B00DL4CH2G/ref=sr_1_4?ie=UTF8&qid=1403627630&sr=8-4&keywords=bluetooth+remote
All of the above are not that expensive (i.e. about $30). The biggest potential downside is that the gym teacher will still have some thing in their hand. Might not be a problem.
If it is a problem, then you could consider a Pebble "smartwatch". In addition to the things like getting notifications on the watch and different watch faces and so on, it does have the ability to control music on an iOS devices. Of course, it cost quite a bit more than those Bluetooth remotes above…as in about $150. So, if you are ONLY using it for the music controlling feature, then it likely is not worth the added cost.
The last overall option is to go to Airplay. With this option, the iPod Touch could stay in the teacher's hand but still play music through some speakers. This option would require there to be WiFi in the location of the gym class, although I suppose you could just use an Airport Express (or some other router) to create a local WiFi network that does not connect to the Internet but does connect to the Airplay speaker. Then you get an Airplay speaker or get an Airport Express and connect any old computer speakers to it.