I don't doubt we'll see a refreshed iPod soon, just not one that has anywhere near the "wow factor" of the iPhone. The stuff you want to get rid of in the iPhone to make it cheaper, isn't sufficiently expensive. The display and battery in the iPhone make up a big chunk of the cost.
iPod already has a screen and a battery. Are there any indications that the battery in the iPhone is substantially more expensive than the one in the iPod? They both have more or less same playback-time when it comes to video and audio. Screen is more expensive in the iPhone, but the price-difference between the iPhone-screen vs. iPod-screen might not be that huge. However, I do expect the new iPod to be a bit more expensive than the current model.
And yes, cell-phone, WiFi and camera do cost quite a bit of money. And part of the cost in the iPhone is the R%D they invested in it. If they release a similar iPod, they could amortize the R&D sooner, as well as getting economies of scale when it comes to components.
Just think about it this way the 8 GB nano and the 30 GB iPod are the same price, how do you think that comes about? The HDD costs less than the flash, but the larger display and battery offset that difference.
Again: What makes you think that the battery in iPhone costs substantially more than the battery in the iPod? And we have no idea what Apple's margins are on the iPhone.
How can Microsoft sell Zune for the same amount of money as Apple sells iPod, even though it has WiFi, bigger screen and recordlabel-kickbacks? And take in to account that Zune is brand new product and they sstill have to pay for it's R&D, whereas iPod is mostly based on R&D that has been paid for.
If you want an HDD based iPod with the iPhone's display and UI you'll need a bigger battery than the iPhone which will offset the cost of removing the camera, phone and WiFi
So, you think that the price-difference between the iPod-battery and the iPhone-battery is more or less the same as the price of WiFi, cell-phone, and camera? Uh, OK...
Fact remains that it would be quite dumb for Apple to have two mediaplayers in the market with vastly different UI's. Apple has already done the needed R&D, it would be dumb for them to NOT use it in the iPod.