There are a few options, none of them all that enticing.
1) Get a LOD. If you want a cheap LOD, try and get the FiiO ones. Not sure if @
PristineNote sells them here, but PM them. Now, bypassing the internal amp of iPod Touch 3G is no guarantee that it will sound better. So, everything comes to the choice of the amplifier which will add a bit more body to the sound without making it overly warm and muddy. No idea of how FiiOs sound though. Long back when I had the iPod Touch 3G, I did not find them all that great even with LOD -> iBasso T3 and even Arrow 3G. TTVJ Slim is supposed to be a little on the warmer side, though I have no personal experience with it.
2) Get a working condition iPod Video 5/5.5G. It's HDD based, bulky, may not have great battery life. But, it certainly sounds far from the cold sound of the Touch 3G. But the downside is you will have to go with the LOD and a good amp. UHA-6S is very transparent and gels well with the iPod, 2SD is certainly more 'etched' with a black background, but I prefer UHA-6S with OPA209. This is a bulky setup, costlier because you are adding a whole new setup and you'll be wanting to upgrade iPod into an iMod or do mods like replacing the HDD and battery - which again add to the cost down the line.
3) Hifiman HM-601 Slim at
$250. I am not a big fan of the bulk (even at 4mm less thick), most likely not so great build quality and high output impedance of the player (I only heard the original, no sign Slim is better in this area). It is a warm sounding player, a different kind of sound compared to iPod Touch and the Clip+, can drive even demanding headphones with the high gain mode. But the downside is that you need a headphone or IEM which meshes and has good synergy with the sound signature and high OI of the 601. It's tough to say which ones will suit your taste without buying and testing them yourself. It's more of a risky experiment. If you end up liking it, it would be worth the effort, otherwise not.
Let me think if there are any other options...